Australia has a treaty with both the United States and New Zealand to cooperate on military matters worldwide.
The Australia , New Zealand , United States Security Treaty ( ANZUS or ANZUS Treaty ) is the 1951 collective security agreement which binds Australia and New Zealand and , separately , Australia and the United States , to co-operate on military matters in the Pacific Ocean region , although today the treaty is taken to relate to conflicts worldwide . Australia . Australia is a member of the United Nations , G20 , Commonwealth of Nations , ANZUS , Organisation for Economic Co-operation and Development ( OECD ) , World Trade Organization , Asia-Pacific Economic Cooperation , and the Pacific Islands Forum .