Australia will gain access to Papua New Guinea's (PNG) military facilities and troops under a key deal that will see the nations come to each other's aid if either is attacked.
Both governments say the deal was born from a yearslong alliance between the two Pacific neighbours, but experts say it is aimed at countering China's growing influence in the region.
The deal ensures China will not have the same access to infrastructure in PNG as it does in other Pacific Islands, said Oliver Nobetau, project director of the Lowy Institute's Australia-PNG network.
It will allow as many as 10,000 Papua New Guineans to serve in Australia's military, and give them the option to become Australian citizens.
With nearly 12 million people, PNG is the largest and most populous South Pacific nation.
China has already significantly shored up trade with Pacific Island nations in recent years and is now trying to establish diplomatic and security beachheads across the region.
Australia and its Western allies, including the United States, have been attempting to counter these efforts.
In 2022, Beijing signed a security deal with the Solomon Islands which has seen Chinese police officers embedded across the country, with another policing agreement forged in 2023.
In response, Canberra last December struck a deal to invest A$190m ($126m; £93m) into the Solomon Islands police force and set up a police training centre, with a similar agreement in place with Tuvalu.
PNG Prime Minister James Marape, who signed this latest agreement with his Australian counterpart Anthony Albanese on Monday, stressed the deal was not born out of geopolitics.
Marape stated, We have told them that Australia is our security partner of choice and they understand our alliances here.
The Pukpuk Treaty, named after the word for crocodile in PNG pidgin, notes that an armed attack on either country would be dangerous to the other's peace and security.
According to the treaty details, the agreement also covers greater collaboration around cyberspace and electromagnetic warfare, with annual joint military exercises scheduled for continued integration of forces.
Critics in PNG have raised concerns that the treaty may undermine its longstanding policy of remaining neutral in geopolitical conflicts. Despite these concerns, analysts perceive the treaty as an essential step in modernizing PNG's military capabilities while enhancing Australia’s strategic positioning in the Pacific.
