PNG Risks Strategic Entanglement in the Australia–PNG Defence Treaty

The proposed Australia–PNG Defence Treaty has been hailed as a milestone in bilateral security cooperation. Canberra frames it as a partnership that will strengthen the PNG Defence Force (PNGDF) through training, infrastructure, and interoperability with the Australian Defence Force (ADF). Yet behind the rhetoric lies a set of risks that have not been openly debated in Port Moresby. The most pressing danger is that PNG could be pulled into conflicts driven not by its own interests, but by Australia’s wider alliance obligations with the United States (US) and other partners.

PNG soldiers are set to join the Australian Defence Force under the new defence treaty, raising tough questions: if Australia goes to war with China alongside its ANZUS and QUAD partners, will PNG troops be drawn in too? Watch the ABC News coverage here.

Unlike the ANZUS treaty, which binds Australia, New Zealand (NZ), and the US to act collectively if attacked, no public draft of the Australia–PNG agreement includes such a clause. On paper, PNG is not being asked to defend Australia against external enemies. However, the push for interoperability—embedding PNGDF personnel in Australian command structures, sharing logistics, and aligning training doctrines—creates informal commitments that can be just as powerful as formal ones. Once forces are integrated, the line between PNG’s decisions and Australia’s decisions begins to blur.

This becomes particularly concerning when viewed through the lens of Australia’s alliance network. Canberra is a long-standing member of the Five Eyes intelligence-sharing arrangement and an increasingly active player in the Quadrilateral Security Dialogue alongside the US, India, and Japan. If tensions with China boil over, especially over Taiwan, Washington would expect Canberra’s support under ANZUS. In that scenario, Canberra would in turn expect Port Moresby to demonstrate solidarity, citing the defence treaty as evidence of shared responsibility.

The WWII precedent should not be ignored. During that war, Papua New Guineans—then under Australian colonial administration—were mobilised to fight Japan, whether as soldiers in the Pacific Islands Regiment or as carriers supporting Australian troops. While PNG is now sovereign, the logic of dependency remains. If Australia fights, will PNG once again find itself in the trenches of someone else’s war? The uncomfortable reality is that the structural pressures today look strikingly similar to those of eighty years ago.

A further lesson can be drawn from NZ’s experience with ANZUS. In the mid-1980s, Wellington adopted a nuclear-free policy and refused entry to US nuclear-capable vessels. This clashed with Washington’s strategic posture, and the US suspended its ANZUS obligations to New Zealand. Though relations were strained, NZ asserted its sovereign right to put national policy above alliance expectations. PNG must pay attention to this precedent: if it signs a defence treaty that leaves room for Australian or US pressure, it will face the same hard choice later—either comply with alliance demands or risk rupturing ties to preserve sovereignty.

The consequences for PNG–China relations would be severe. Beijing is one of PNG’s largest trading partners, a key provider of infrastructure loans, and a central player in education exchange programs. If PNGDF soldiers fought against Chinese troops—even indirectly under the ADF flag—China would not view PNG as neutral. Retaliation could take the form of aid withdrawal, market closures, or suspension of scholarships for PNG students. What looks like loyalty to Australia could amount to economic self-sabotage.

Another risk lies in the erosion of PNG’s sovereignty. For decades, Port Moresby has insisted on a foreign policy doctrine of “friends to all, enemies to none.” By signing onto a treaty that deepens military integration with Australia but leaves ambiguous the limits of deployment, PNG risks surrendering its independent choice. Sovereignty is not only about flag and constitution; it is also about the ability to say no when great powers demand compliance. Without explicit safeguards, PNG may discover that the right to choose has been hollowed out in practice.

None of this is to deny that cooperation with Australia has clear benefits. The PNGDF requires urgent investment in training, logistics, and disaster response capabilities. Australia is well placed to provide this support, and PNG cannot ignore the value of working with its closest neighbour. But the costs must also be weighed. A treaty that secures short-term benefits at the expense of long-term strategic autonomy may prove to be a bargain too costly for PNG to afford. Unless explicit safeguards are built into the text, PNG risks repeating history—once again fighting “for Australia,” not because it chose to, but because it had no choice.