Japan–Australia relations at 50: Why middle power cooperation matters in an era of US–China rivalry

■Japan–Australia relations enter a new phase
Japan–Australia relations are becoming a test of Japan’s strategic intent. They are moving into a phase that can no longer be understood as a simple extension of the past. The 1976 Basic Treaty of Friendship and Cooperation institutionalised an economic relationship centred on resources and energy. Today, that relationship has expanded to include security, advanced technologies and people-to-people exchange.
In recent years, cooperation in the security domain has deepened in ways that are increasingly visible. The updated Joint Declaration on Security Cooperation in 2022 and the entry into force of the Reciprocal Access Agreement (RAA) have significantly advanced bilateral ties. The framework linking defence authorities (FSDC) is also being used more actively. Taken together, these developments point to a relationship that is moving into what is often described as a ‘quasi-alliance’.
A particularly clear sign of this shift is the contract concluded between Japan and Australia for the joint development and export of a vessel based on the upgraded Mogami-class frigate. More than a procurement arrangement, it reflects a shift toward shared defence capabilities. That two countries which once fought across the Pacific are now moving towards cooperation built on a shared naval platform speaks to a qualitative change in the relationship. It suggests that Japan–Australia ties are already moving closer to what could reasonably be seen as a close partnership.
At the same time, the relationship remains heavily weighted toward traditional sectors, with cooperation still concentrated in areas such as resources, energy and security, while investment in emerging sectors and people-to-people exchange remains limited. Efforts across these domains are progressing, but largely in parallel rather than as part of a clearly integrated strategy. The 50th anniversary of the Basic Treaty provides an opportunity to reconsider how these different elements should be brought together.
The key is not simply to expand cooperation in individual areas, but to connect them. From resource supply and processing to technological development and human capital formation, the relationship needs to be approached as an integrated system rather than a set of separate tracks. In particular, given the risks to energy supply arising from instability in the Middle East and past experience of economic coercion, strengthening supply chains — especially for critical minerals — has become unavoidable. At the same time, investment in emerging areas such as green iron and hydrogen, along with the movement and development of the next generation of talent, will shape whether the relationship can be sustained over the long term.

■Japan’s role in an era of US–China rivalry
The need for such a reconfiguration reflects deeper structural changes in Japan’s strategic environment. The Japan–US alliance remains the cornerstone of diplomacy and security, but uncertainty surrounding the nature of US engagement is growing. At the same time, economic ties with China remain deep, even as tensions in the diplomatic and security domains continue to intensify. As US–China rivalry becomes more prolonged, Japan is required to balance alliance commitments with continued engagement with China. This is happening at a time when shifts in US engagement and rising geopolitical risks are reshaping the region.
In this context, Japan needs to maintain the Japan–US alliance as the foundation of its strategy, while avoiding excessive dependence and expanding its strategic options. This is where middle power cooperation becomes central. Japan and Australia share a similar structural position — both are US allies while maintaining economic ties with China.
Differences in geography and industrial structure create strong complementarities. Under these conditions, Australia stands out as one of Japan’s most important partners in advancing such cooperation.
Economic and security considerations are no longer separable. Supply chains and technologies are increasingly treated as strategic assets. Maintaining openness while strengthening resilience and managing risk is no longer simply a policy choice, but a necessity. Japan must pursue a form of economic diplomacy that balances openness with security in a pragmatic way.
Japan’s role is not limited to participating in middle power cooperation. It also lies in linking multiple layers of frameworks — including economic partnerships such as CPTPP and RCEP, economic security arrangements such as IPEF, and minilateral cooperation such as the QUAD — and in doing so, playing a more active role in shaping the regional order.
As US–China rivalry continues, Japan faces a fundamental choice: whether to adjust passively to external pressures or to engage more actively in shaping the regional order through cooperation with other middle powers. In this context, Japan–Australia relations go beyond a bilateral partnership. They are becoming a test of Japan’s strategic intent and will likely shape the trajectory of the regional order in the years ahead. The 50th anniversary is not an endpoint, but the beginning of that test.

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