Australia and Papua New Guinea have taken a major step to reshape the security landscape of the South Pacific, signing a landmark defense pact aimed squarely at countering China's growing influence in the region. The agreement, announced by Australian Prime Minister Anthony Albanese on September 15, 2025, and set to be formally signed on September 17 in Port Moresby, marks a significant deepening of military and strategic ties between the two nations. The timing is notable—just a day after Papua New Guinea celebrates its 50th anniversary of independence from Australia, a symbolic backdrop for an accord that looks to the future while acknowledging a shared past.
"It is a very significant upgrade in our defense relationship," Albanese told the Australian Broadcasting Corporation, speaking from Perth before flying to Papua New Guinea. He emphasized the mutual nature of the pact, saying, "It provides for mutual defense, which means that we will provide support for each other, provide for an integration of our interoperability of our assets and our respective defense forces."
Under the new agreement, the defense forces of both countries will be integrated to an unprecedented degree. This means not only closer operational coordination but also the opportunity for citizens of Australia and Papua New Guinea to serve in either country's military. In a move designed to further cement the partnership, Australia will offer its citizenship as an incentive for Papua New Guineans who choose to enlist in the Australian military—a significant shift from current policy, which restricts recruitment to citizens of Five Eyes intelligence-sharing partners (the United States, Britain, Canada, and New Zealand).
With a population of nearly 12 million, Papua New Guinea stands as the most populous nation in the South Pacific after Australia, which has 27 million people. The pact is set to have far-reaching implications, not only for the two countries involved but for the broader region, where the strategic rivalry between Western allies and China has been intensifying.
The urgency behind the agreement is clear. According to ABC and other international reports, three Pacific island nations have switched diplomatic recognition from Taiwan to Beijing since 2019, a trend that has alarmed both the United States and its allies. China's expanding presence in the region has included security cooperation and police training in countries such as Fiji, Kiribati, Samoa, Solomon Islands, and Vanuatu. For Australia and its partners, these developments represent a challenge to the traditional security order in the Pacific.
U.S. Deputy Secretary of State Christopher Landau is expected to attend the independence celebrations and the signing ceremony in Port Moresby, underscoring the international significance of the event and the broad coalition of interests at play.
The new treaty builds on a 2023 security agreement between Australia and Papua New Guinea, which had already broadened defense cooperation and reinforced Australia’s position as the preferred security partner in the region. That earlier agreement, however, was not without controversy. Its signing was delayed by six months after a separate security deal between the United States and Papua New Guinea sparked widespread protests in May 2023, with critics arguing that the U.S. pact threatened Papua New Guinea's sovereignty.
Concerns about sovereignty and the exclusivity of security relationships remain front and center for many Pacific island nations. Oliver Nobetau, project director of the Australia–Papua New Guinea Network at the Sydney-based Lowy Institute, noted that any language in the new pact suggesting Australia is the exclusive security partner for Papua New Guinea would be significant. "If there’s any wording around Australia being the security partner of choice for a country like Papua New Guinea, that would be a big win" for Australia, Nobetau told the press. But he also cautioned that Pacific countries, and Papua New Guinea in particular, have been "quite adamant about protecting their sovereignty, which means removing the sort of language that excludes third-party partnerships."
Australian Defense Minister Richard Marles described the new bilateral treaty as "transformational," emphasizing that it would replace the agreement struck in 1977, shortly after Papua New Guinea gained independence. Marles also indicated that Australia is continuing talks with Fiji and Tonga to advance bilateral defense cooperation, signaling a broader regional strategy to shore up alliances and partnerships.
For Papua New Guinea, the new pact offers both opportunities and challenges. The ability for its citizens to serve in the Australian military, potentially gaining Australian citizenship, could be a powerful incentive—especially for young people seeking new opportunities. At the same time, the country’s leaders must balance the benefits of closer ties with Australia against the desire to maintain sovereignty and avoid alienating other potential partners, particularly China, which remains a major source of infrastructure funding and investment in the region.
The geopolitical context is complex. Many Pacific island nations have made it clear that they do not wish to be forced to choose sides in the intensifying competition between the U.S. and its allies on one hand, and China on the other. As negotiations for a security and economic treaty between Australia and Vanuatu have shown, concerns about how such deals might impact access to Chinese infrastructure funding can delay or complicate agreements. Vanuatu, for example, has extended negotiations with Australia due to internal concerns over how the pact might affect its relationship with China.
Meanwhile, the United States and its allies are watching developments closely. The presence of Deputy Secretary Landau at the signing ceremony is a signal of American interest in ensuring that the Pacific remains a region where Western values and security arrangements prevail. The U.S. has been particularly wary of China's efforts to forge security ties with Pacific nations, viewing them as part of a broader strategy to project power in the Indo-Pacific and challenge the existing order.
For Australia, the stakes are high. The new defense pact with Papua New Guinea is both a response to immediate concerns about Chinese influence and a long-term investment in regional stability. By offering citizenship and integrating military service, Australia is betting that stronger people-to-people ties and shared defense interests will help anchor Papua New Guinea in its orbit.
Yet, the agreement is not without risks. Any perception that Australia is seeking to dominate or limit Papua New Guinea’s options could provoke backlash, both domestically and among other Pacific island nations. The region’s leaders have repeatedly emphasized the importance of maintaining autonomy and the freedom to engage with multiple partners.
As the ink dries on the new defense pact, the eyes of the region—and indeed, the world—will be on how Australia and Papua New Guinea implement their ambitious vision. The coming months and years will reveal whether the agreement succeeds in strengthening security and cooperation without undermining the delicate balance of sovereignty and partnership that defines the Pacific.
For now, the signing of the pact stands as a testament to the enduring ties between Australia and Papua New Guinea, and to the shifting currents of power and influence in one of the world’s most strategically vital regions.