25 November 2025
IP25109 | The Australia–Indonesia Treaty on Common Security: Strengthening Trust Between Two Regional Partners
KEY TAKEAWAYS
• Leaders of Australia and Indonesia recently announced that both governments are working to finalise a new bilateral security treaty.
• The proposed treaty does not oblige each nation to follow the course taken by the other nation to deal with future security challenges.
• The treaty is a measure to strengthen trust between Indonesian and Australian leaders and sustain the special relationship between the two nations.
COMMENTARY
On 12 November 2025, Australian Prime Minister Anthony Albanese announced that the governments of Australia and Indonesia were about to conclude a new bilateral security treaty which would transform the two nations’ long-term partnership. The announcement was made alongside Indonesian President Prabowo Subianto, who was in Australia on a state visit.
The new treaty is not a formal alliance between the two nations as it does not require both nations to assist in each other’s defence in the event either of them faces an attack from an external adversary. Such an alliance would violate Indonesia’s long-standing “free and active” (bebas aktif) foreign policy principle, which prohibits Indonesia from being a party to a formal security alliance with any nation – regardless of whether the latter is a great power, rising power or a middle power like Australia.
Nonetheless, the treaty is widely described by analysts as a “trust-building” agreement between two nations that, while long-time bilateral partners, do not always see eye-to-eye on the most important security challenges they face; the two are likely to take very different sets of policy actions to resolve any potential crisis that may arise from the increased geopolitical rivalry in the Indo-Pacific region.
Key Provisions of The New Treaty
The most important provision of the Australia–Indonesia Treaty on Common Security calls for the two nations to develop a shared operating architecture of the security environment faced by both nations and the region as a whole through regular consultations at the leader and ministerial levels. Such consultations are required both in general and when one or both countries are facing a challenge from an external adversary.
However, in considering measures that may be taken when one or both nations are facing a potential threat, one proposed clause contains the qualifier “if appropriate”, meaning either party is not obliged to follow the measures recommended by the other party to resolve the potential security challenge.
Furthermore, another proposed clause states that Australia and Indonesia “agree to promote – in accordance with the policies and priorities of each – mutually beneficial cooperative activities in the security field”. This seems to be an escape clause that while opening the possibility for future joint security cooperation and activities between the two nations does not require either party to participate in such cooperative activities.
These clauses seem to be drafted to give Indonesia the leeway to refrain from assisting Australia when the latter takes a certain course of actions in response to a future security challenge, effectively ensuring that Indonesia’s free and active nonalignment principle is not violated.
Rationale for the New Treaty
At first, one might wonder what new measures of cooperation the new treaty entails, given that Australia and Indonesia are already parties to several bilateral defence and security cooperation agreements. For instance, the 2006 Australia–Indonesia Security Cooperation Agreement (also known as the Lombok Treaty) provides for a wide range of defence cooperation initiatives, including military education and training, law enforcement, counterterrorism, and defence technologies and capabilities.
One must look at the 1995 Agreement on Maintaining Security (AMS) between Australia and Indonesia to see the main purpose of the new treaty. Both the AMS and the new treaty require consultation between the two nations, particularly on issues of “adverse challenges” to their common security interests. The main difference is that the new treaty will require consultation at leader level in addition to ministerial level – a recognition that consultation at both levels is essential to ensure coherent policymaking.
The proposed treaty is crafted in the midst of increasing geopolitical rivalry between the United States and China, which has the potential of forcing Australia and Indonesia into making different strategic choices, given their different historical foreign policy alignments. In addition, Australia is anxious that Russia might seek to increase its security footprint in the Indo-Pacific region by securing access for its aircraft to conduct military operations in the region that could be utilised to gather intelligence on Australia and other countries.
Australia is an ally of the United States bound by the 1951 Australia, New Zealand and the United States (ANZUS) treaty. It is widely expected to lend assistance to the United States in any potential future conflict between the latter and other nations due to its ANZUS obligations. Meanwhile, Indonesia is expected to follow its long-standing free and active principle, which prohibits becoming a party to any security alliance and alignment should the above scenario be realised. Given its adherence to the principle, Indonesia is expected to remain neutral in any future conflict that might occur in the Indo-Pacific region.
These differing perspectives on global and regional security have occasionally created tension between Indonesia and Australia notwithstanding the close bilateral relationship the two countries have forged from the time of Indonesia’s independence in 1945.
In October 2021, the Indonesian Foreign Ministry (Kemlu) issued a statement of concern regarding AUKUS, the newly declared trilateral security partnership between Australia, the United Kingdom and the United States to deploy US-built nuclear-powered submarines as Australian military assets. Specifically, Kemlu’s statement expressed “deep concern over the continuing arms race and power projection in the region”. Nonetheless, in May 2023, then Indonesian President Joko Widodo clarified that in his view, AUKUS and the Quad – a minilateral institution consisting of Australia, India, Japan and the United States – were partners of, not competing institutions to, ASEAN.
More recently, Australia expressed strong concerns regarding news reports that Indonesia had received a request from Moscow to allow Russian aircraft to be based at the Manuhua Air Force Base in Papua province. These reports were denied by Indonesian Defence Minister Sjafrie Sjamsuddin, who also stated that “there would be no Russian air force planes based in Indonesia”.
Nonetheless, questions lingered over whether such a conversation between Jakarta and Moscow defence authorities regarding the matter had in fact taken place and whether Jakarta had properly notified Canberra about this matter.
While Article 3 of the Lombok Treaty on defence cooperation calls for the Australian and Indonesian defence forces to have “regular consultation on defence and security issues of common concern; and on their respective defence policies”, policymakers later thought that this language was not as clear as Article 2 of the AMS agreement, which calls for both parties to “to consult each other in the case of adverse challenges to either party or to their common security interests.” The language of the latter is reflected in the readout of the proposed new treaty released by the office of Australian Foreign Minister Penny Wong.
Concluding Thoughts
Given these considerations, both Jakarta and Canberra concluded that a new treaty that reaffirms the mutual obligations of Indonesian and Australian policymakers to consult each other on security issues affecting them both bilaterally and regionally was needed.
Under the proposed treaty, Australia and Indonesia intend to consult each other when they perceive there is a security challenge that may adversely affect both nations and the region as a whole. The treaty intends to develop mutual trust between Indonesia and Australia and encourage leaders of each nation to communicate with the other in good faith. Each nation is to inform the other regarding its intended course of action to resolve the challenge while not obliging the other to take similar action. Most importantly, the new treaty is aimed at preventing diplomatic surprises and their potential fallout.
By finalising the treaty, both nations are ensuring that notwithstanding any potential different actions they might take to address a future conflict, Indonesia and Australia will remain reliable friends and partners, thereby affirming the special relationship both have cultivated for over eight decades, a relationship with positive spillovers for the region as a whole.
Alexander R. Arifianto is Senior Fellow and Coordinator of the Indonesia Programme at the Institute of Defence and Strategic Studies (IDSS), S. Rajaratnam School of International Studies (RSIS).
KEY TAKEAWAYS
• Leaders of Australia and Indonesia recently announced that both governments are working to finalise a new bilateral security treaty.
• The proposed treaty does not oblige each nation to follow the course taken by the other nation to deal with future security challenges.
• The treaty is a measure to strengthen trust between Indonesian and Australian leaders and sustain the special relationship between the two nations.
COMMENTARY
On 12 November 2025, Australian Prime Minister Anthony Albanese announced that the governments of Australia and Indonesia were about to conclude a new bilateral security treaty which would transform the two nations’ long-term partnership. The announcement was made alongside Indonesian President Prabowo Subianto, who was in Australia on a state visit.
The new treaty is not a formal alliance between the two nations as it does not require both nations to assist in each other’s defence in the event either of them faces an attack from an external adversary. Such an alliance would violate Indonesia’s long-standing “free and active” (bebas aktif) foreign policy principle, which prohibits Indonesia from being a party to a formal security alliance with any nation – regardless of whether the latter is a great power, rising power or a middle power like Australia.
Nonetheless, the treaty is widely described by analysts as a “trust-building” agreement between two nations that, while long-time bilateral partners, do not always see eye-to-eye on the most important security challenges they face; the two are likely to take very different sets of policy actions to resolve any potential crisis that may arise from the increased geopolitical rivalry in the Indo-Pacific region.
Key Provisions of The New Treaty
The most important provision of the Australia–Indonesia Treaty on Common Security calls for the two nations to develop a shared operating architecture of the security environment faced by both nations and the region as a whole through regular consultations at the leader and ministerial levels. Such consultations are required both in general and when one or both countries are facing a challenge from an external adversary.
However, in considering measures that may be taken when one or both nations are facing a potential threat, one proposed clause contains the qualifier “if appropriate”, meaning either party is not obliged to follow the measures recommended by the other party to resolve the potential security challenge.
Furthermore, another proposed clause states that Australia and Indonesia “agree to promote – in accordance with the policies and priorities of each – mutually beneficial cooperative activities in the security field”. This seems to be an escape clause that while opening the possibility for future joint security cooperation and activities between the two nations does not require either party to participate in such cooperative activities.
These clauses seem to be drafted to give Indonesia the leeway to refrain from assisting Australia when the latter takes a certain course of actions in response to a future security challenge, effectively ensuring that Indonesia’s free and active nonalignment principle is not violated.
Rationale for the New Treaty
At first, one might wonder what new measures of cooperation the new treaty entails, given that Australia and Indonesia are already parties to several bilateral defence and security cooperation agreements. For instance, the 2006 Australia–Indonesia Security Cooperation Agreement (also known as the Lombok Treaty) provides for a wide range of defence cooperation initiatives, including military education and training, law enforcement, counterterrorism, and defence technologies and capabilities.
One must look at the 1995 Agreement on Maintaining Security (AMS) between Australia and Indonesia to see the main purpose of the new treaty. Both the AMS and the new treaty require consultation between the two nations, particularly on issues of “adverse challenges” to their common security interests. The main difference is that the new treaty will require consultation at leader level in addition to ministerial level – a recognition that consultation at both levels is essential to ensure coherent policymaking.
The proposed treaty is crafted in the midst of increasing geopolitical rivalry between the United States and China, which has the potential of forcing Australia and Indonesia into making different strategic choices, given their different historical foreign policy alignments. In addition, Australia is anxious that Russia might seek to increase its security footprint in the Indo-Pacific region by securing access for its aircraft to conduct military operations in the region that could be utilised to gather intelligence on Australia and other countries.
Australia is an ally of the United States bound by the 1951 Australia, New Zealand and the United States (ANZUS) treaty. It is widely expected to lend assistance to the United States in any potential future conflict between the latter and other nations due to its ANZUS obligations. Meanwhile, Indonesia is expected to follow its long-standing free and active principle, which prohibits becoming a party to any security alliance and alignment should the above scenario be realised. Given its adherence to the principle, Indonesia is expected to remain neutral in any future conflict that might occur in the Indo-Pacific region.
These differing perspectives on global and regional security have occasionally created tension between Indonesia and Australia notwithstanding the close bilateral relationship the two countries have forged from the time of Indonesia’s independence in 1945.
In October 2021, the Indonesian Foreign Ministry (Kemlu) issued a statement of concern regarding AUKUS, the newly declared trilateral security partnership between Australia, the United Kingdom and the United States to deploy US-built nuclear-powered submarines as Australian military assets. Specifically, Kemlu’s statement expressed “deep concern over the continuing arms race and power projection in the region”. Nonetheless, in May 2023, then Indonesian President Joko Widodo clarified that in his view, AUKUS and the Quad – a minilateral institution consisting of Australia, India, Japan and the United States – were partners of, not competing institutions to, ASEAN.
More recently, Australia expressed strong concerns regarding news reports that Indonesia had received a request from Moscow to allow Russian aircraft to be based at the Manuhua Air Force Base in Papua province. These reports were denied by Indonesian Defence Minister Sjafrie Sjamsuddin, who also stated that “there would be no Russian air force planes based in Indonesia”.
Nonetheless, questions lingered over whether such a conversation between Jakarta and Moscow defence authorities regarding the matter had in fact taken place and whether Jakarta had properly notified Canberra about this matter.
While Article 3 of the Lombok Treaty on defence cooperation calls for the Australian and Indonesian defence forces to have “regular consultation on defence and security issues of common concern; and on their respective defence policies”, policymakers later thought that this language was not as clear as Article 2 of the AMS agreement, which calls for both parties to “to consult each other in the case of adverse challenges to either party or to their common security interests.” The language of the latter is reflected in the readout of the proposed new treaty released by the office of Australian Foreign Minister Penny Wong.
Concluding Thoughts
Given these considerations, both Jakarta and Canberra concluded that a new treaty that reaffirms the mutual obligations of Indonesian and Australian policymakers to consult each other on security issues affecting them both bilaterally and regionally was needed.
Under the proposed treaty, Australia and Indonesia intend to consult each other when they perceive there is a security challenge that may adversely affect both nations and the region as a whole. The treaty intends to develop mutual trust between Indonesia and Australia and encourage leaders of each nation to communicate with the other in good faith. Each nation is to inform the other regarding its intended course of action to resolve the challenge while not obliging the other to take similar action. Most importantly, the new treaty is aimed at preventing diplomatic surprises and their potential fallout.
By finalising the treaty, both nations are ensuring that notwithstanding any potential different actions they might take to address a future conflict, Indonesia and Australia will remain reliable friends and partners, thereby affirming the special relationship both have cultivated for over eight decades, a relationship with positive spillovers for the region as a whole.
Alexander R. Arifianto is Senior Fellow and Coordinator of the Indonesia Programme at the Institute of Defence and Strategic Studies (IDSS), S. Rajaratnam School of International Studies (RSIS).
