The leaders of Australia and Papua New Guinea (PNG) signed a major bilateral defense treaty in October 2025 that commits the countries to defend each other if attacked.
Australian Prime Minister Anthony Albanese and PNG Prime Minister James Marape described the agreement as a mutual defense treaty that will enable unprecedented integration of the nations’ defense forces.
It is Australia’s only alliance-level security pact other than the ANZUS Treaty signed with New Zealand and the United States in 1951. It is the first such treaty for PNG, Australia’s nearest neighbor and former territory.
The agreement will take effect upon ratification by each nation’s parliament.
“This treaty contains a mutual defense obligation similar to Australia’s ANZUS Treaty commitments, where we declare that in the event of an armed attack on either of our countries, we would both act to meet the common danger,” Albanese said at a news conference with Marape in Canberra.
“Both our nations have also agreed not to undertake any activities or enter into any agreements that would compromise the implementation of this treaty,” he said.
Marape said the treaty does not erode PNG’s dominant foreign policy: friend to all, enemy to none. He said the treaty consolidates the nation’s security partnership with Australia “with no intent of creating enemies elsewhere.”
Australia and the U.S. have increased defense engagements with PNG, which is seen as a strategic partner in countering China’s attempts to expand its influence in the Pacific.
Australia has bolstered relations with island nations in the region since 2022, when Beijing struck a security deal with Solomon Islands that raised the specter of China establishing a naval base in the South Pacific.
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