A month after signing a major security treaty, Indonesia and Australia plan to expand their security cooperation to include Japan and Papua New Guinea, Indonesia’s defense ​minister said yesterday.

Speaking after a meeting with Australian Defense Minister Richard Marles in Jakarta, Sjafrie Sjamsoeddin said that the two nations would establish two trilateral security arrangements: one with Indonesia, Australia, and Japan, and another between Indonesia, Australia, and Papua New Guinea.

“The Indonesia-Australia bilateral cooperation is now being expanded into a trilateral format… specifically in the area of defense professionalism,” Sjafrie told a joint press briefing, the Jakarta Post reported.

Marles told reporters the proposed trilateral cooperation was “a really important piece of architecture” for advancing peace and stability in the region. He later wrote in a post on X that the meeting with Sjafrie was “a great opportunity to discuss the strong momentum that exists in growing our defense relationship as we work together to support a secure and peaceful Indo-Pacific region.”

The announcement comes at a productive time for Indonesia-Australia defense relations. Last month, Jakarta and Canberra signed the Australia-Indonesia Treaty on Common Security – known as the Jakarta Treaty for short – a major agreement that commits them to increased security consultations. Under the treaty, which was based on the 1995 security treaty that was signed by President Suharto and Prime Minister Paul Keating, the two countries agreed to develop joint military training facilities in Indonesia as well as to increase cooperation and information sharing, including consulting “at a leader and ministerial level” on security matters faced by both countries.

Sjafrie and Marles also said that they had discussed the possibility of establishing a defense training facility on the small island of Morotai in North Maluku. Morotai served as a major Japanese base during World War II, before being captured by Allied forces in 1944. It was then developed into a strategic air base and played an important role in the liberation of the Philippines during 1944 and 1945. An operational airfield still exists on the southwestern end of the island. “We will work together to improve and utilize it,” Sjafrie said of the site.

Marles told reporters that the Morotai facility would belong to Indonesia, and that Jakarta would determine how it would be used, but that “there ​would be opportunities we see for Australia to engage in training there.” Sjafrie said that military personnel from countries such as the Philippines and Singapore would also have access to the facility. The Australian defense minister also said that, as per the Jakarta Treaty, an Indonesian with the rank of colonel would embed with Australian troops from early next year as a deputy commander of the 1st Brigade of the Australian Army in Darwin.

While details of the planned trilateral agreements have yet to be announced, the expansion of this bilateral cooperation to include Papua New Guinea and Japan makes a good deal of strategic sense for the nations involved. Last October, Australia signed a Mutual Defense Treaty with Papua New Guinea, and in 2022, signed a Reciprocal Access Agreement with Japan that facilitates the deployment of Australian and Japanese forces to both nations for military exercises. Likewise, Indonesia has recently expanded its defense cooperation with both PNG, with a focus on border security and educational exchanges, and Japan, which has transcended its role as a source of economic assistance to become an important partner in maritime security.

In December, Indonesia, Australia, and PNG convened their first trilateral Defense Ministers’ Meeting in Port Moresby. During the meeting, PNG Defense Minister Billy Joseph said that the three-way meeting “allows us to deepen trust, harmonize our approaches and enhance coordination on issues that affect all of us, including border management, maritime security, humanitarian assistance and disaster responses, defense capability development and broader regional peace and stability.”

The efforts to advance these relationships are a clear response to the fraying of the international order amid the emergence of an increasingly assertive China and a distant, mercurial, and increasingly distracted United States under President Donald Trump. As long as things continue to unravel, it is likely that similar trilateral and minilateral security agreements will continue to proliferate.