Australia and Japan are being urged to formalize their security cooperation through a comprehensive treaty that would consolidate their alliances with the United States and strengthen regional deterrence amid growing geopolitical uncertainties. A report by the National Security College, authored by regional security analyst Euan Graham, advocates for a “grand bargain” between the two countries. This arrangement would see Japan receiving preferential access to Australia’s energy and critical minerals supplies in exchange for investments in Australia’s critical minerals processing and defense industries, as well as joint efforts to secure supply routes between the nations.
The call for a treaty builds on recent developments in bilateral defense relations, including the 2023 Reciprocal Access Agreement, the 2026 Joint Statement on Enhanced Defence and Security Co-operation, and a $10 billion deal for the supply of Mogami-class frigates signed earlier this year. Australia and Japan, regarded as Washington’s two most important Pacific allies, also engage in multilayered security collaborations such as the Quadrilateral Security Dialogue (Quad) and a smaller grouping known as the Squad, which includes the Philippines instead of India.
Despite the depth of current cooperation, Australia and Japan lack a legally binding pact that requires consultation or joint response to security threats affecting either country’s sovereignty or the wider region. Australia has such agreements with neighboring countries including Papua New Guinea, Indonesia, and Fiji. The report stresses that upgrading bilateral ties to treaty status is justified by the “complete trust” and strategic alignment that Defense Minister Richard Marles has highlighted in recent remarks.
The evolving security environment in the Indo-Pacific—marked by doubts over the long-term reliability of the U.S. security commitment, increasing demands from Washington for allied countries to share more of the defense burden, and intensifying Chinese regional assertiveness—provides a strong rationale for formalizing closer Japan-Australia security ties. While Japan has shown cautious openness to the idea, some voices in Canberra remain concerned that such a treaty might entangle Australia in potential conflicts involving China.
Graham contends these concerns can be mitigated by following the model of Australia’s recent Treaty of Commonwealth with Indonesia, which stops short of a mutual defense pact but commits both nations to consultations in the event of emerging threats. “Security is not just about protecting against threats that exist in bad places. Defence and security is also about protecting trade and prosperity,” Graham said. He noted Japan’s recognition of energy and critical minerals as strategic assets and highlighted Tokyo’s recent shift toward a more proactive defense posture. This year, Japan has relaxed long-standing restrictions on arms exports and signaled its ambition to act as a principal security partner and defense supplier in the Indo-Pacific.
A treaty encompassing mutual security, energy, and critical minerals cooperation could yield substantial benefits for both countries. Japan’s willingness to invest in Australian defense infrastructure—such as the Henderson shipyards and explosives ordnance facilities—could deepen strategic and economic ties. Graham suggested that Australia’s geographic distance from Chinese missile threats offers Japan strategic depth, enhancing Australia’s significance in Japan’s broader security calculus.
Such an arrangement, he argued, would not merely serve to align with U.S. policy but would represent a natural progression in the evolving strategic and economic relationship between Australia and Japan.