Australia and Papua New Guinea have entered a mutual defense agreement amid increased security tensions in the Indo-Pacific.
The Pukpuk Treaty — named for Papua New Guinea’s word for crocodile — signed in Canberra, Australia, in October 2025, states that the two nations will come to each other’s defense if either is attacked. The agreement also provides for the expansion and modernization of Australia’s and Papua New Guinea’s defense relationship, including the potential military recruitment of each country’s citizens, and greater collaboration around cyberspace and electromagnetic warfare, according to BBC News.
“Building on our countries’ deep strategic trust and respect, the treaty contains mutual defense obligations,” a news release from Australian Prime Minister Anthony Albanese’s office read. “Both countries recognize an armed attack on either would be a danger to the peace and security of both and declare they would act together to meet the common danger.”
The treaty signing followed a September 2025 joint communique issued by Albanese and Papua New Guinea Prime Minister James Marape providing details of the agreement, which were approved by each nation’s governments. Core principles included increasing interoperability, a recruitment pathway for Papua New Guinea citizens into the Australian Defence Force, and acknowledgement of the countries’ respect for one another’s “sovereignty, independence and territorial integrity.”
The agreement allows up to 10,000 Papua New Guineans to serve in Australia’s military and gives them the option to become Australian citizens.
The Pukpuk Treaty is Australia’s only alliance-level security pact other than the ANZUS (Australia, New Zealand and United States) Security Treaty signed in 1951, according to The Associated Press. It is the first such treaty for Papua New Guinea, Australia’s nearest neighbor and former colony.
Papua New Guinea and the U.S. have a defense cooperation agreement, signed in 2023, to collaborate on military exercises and maritime law enforcement.
“This treaty contains a mutual defense obligation similar to Australia’s ANZUS Treaty commitments, where we declare that in the event of an armed attack on either of our countries, we would both act to meet the common danger,” Albanese told reporters at a joint news conference with Marape at Australia’s Parliament House.
The agreement comes as Australia, the U.S. and Western Allies have increased efforts to counter Beijing’s growing influence and investments in the Indo-Pacific. In December 2024, Australia agreed to invest in the Solomon Islands police force and set up a police training center, with a similar agreement in place with Tuvalu. Australia also signed a $328 million security and business deal with Vanuatu.
Pukpuk ensures the Chinese Communist Party will not have the same access to infrastructure as it does in other Pacific Islands, Oliver Nobetau, project director of the Australia-Papua New Guinea network at the Lowy Institute, a think tank focused on Indo-Pacific issues, told the BBC. The deal also includes annual joint military exercises that are about “strategic messaging to show the interoperability of the forces and their ability to face an external threat in the region and how quickly they can organize themselves and deploy,” he said.
Marape said his government has been transparent with Beijing about its partnership with Australia.
“We have told [China] that Australia is our security partner of choice and they understand our alliances here,” he said, according to the BBC. “Other aspects of our relations have never been compromised. By continuing to build our security relationships in the region, we safeguard our own security.”