Australia is a member of 8 intergovernmental teams.
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 . Asia-Pacific Economic Cooperation ( APEC ) is a forum for 21 Pacific Rim member economies that promotes free trade throughout the Asia-Pacific region . 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 . The Commonwealth of Nations ( formerly the British Commonwealth ) , also known as simply the Commonwealth , is an intergovernmental organisation of 52 member states that are mostly former territories of the British Empire . The G20 ( or G-20 or Group of Twenty ) is an international forum for the governments and central bank governors from 20 major economies . The Organisation for Economic Co-operation and Development ( OECD ) ( Organisation de coopération et de développement économiques , OCDE ) is an intergovernmental economic organisation with 35 member countries , founded in 1960 to stimulate economic progress and world trade . The Pacific Islands Forum is an inter-governmental organization that aims to enhance cooperation between the independent countries of the Pacific Ocean . The United Nations ( UN ) is an intergovernmental organization to promote international co-operation and to create and maintain international order . The World Trade Organization ( WTO ) is an intergovernmental organization that regulates international trade .