New Zealand and the Cook Islands have signed a defence and security declaration, ending a year-long diplomatic row that erupted after the Cook Islands struck strategic agreements with China.

The Cook Islands was a dependent New Zealand colony from 1901-65 but has since operated as a self-governing nation in “free association” with New Zealand. Its roughly 17,000 citizens hold New Zealand citizenship. There are obligations between the two nations to regularly consult on matters of defence and security.

In February 2025, New Zealand expressed “significant concern” about a lack of transparency over the Cook Islands’ decision to sign a strategic partnership deal with China covering deep-sea mining, regional cooperation and economic issues.

It marked the first time the Cook Islands had struck a major deal with a country outside its traditional partners – New Zealand and Australia – causing concern within those countries over China’s push for influence in the Pacific.

New Zealand, the Cook Islands’ biggest funder, responded by halting millions of dollars in aid to the nation, which the Cook Islands’ prime minister, Mark Brown, described as “patronising” and “inconsistent with modern partnership”.

On Thursday, relations between the two nations improved, after the signing of declaration that requires both parties to act in good faith and consult on matters of defence and security.

New Zealand’s foreign affairs minister, Winston Peters, said it was no secret the two governments had faced a series of “serious disagreements” since late 2024, but the declaration was about “setting a course together for the future” and providing clarity over the relationship.

Peters said: “The strategic environment we face is more complex and contested today than at any other point since New Zealand and the Cook Islands formed our free association relationship in 1965.

“In that context, it’s vital that New Zealand and the Cook Islands are clear – with one another and third parties – about the nature of our special relationship and our responsibilities to one another in the defence and security domains.”

New Zealand would resume roughly NZ$29.8m ($17.1m) in annual funding support, he said.

Peters added: “We are pleased to now have a shared certainty about the contours of that relationship, and we are grateful to prime minister Brown and his government for the constructive way they approached the negotiation of this declaration.”

Brown said the agreement was about “moving forward”.

He said: “This declaration is about security and defence across our region, and I’m confident that the provisions we have in this declaration will address any concerns that may have occurred in the past.”

Brown said the defence pact with New Zealand would not affect the Cook Islands’ deal with China, but Peters said that deal was no longer a concern.

“This declaration resolves this former ambiguity and provides clarity to both governments so that we can move forward focused on the future, not the past,” Peters said.

“If anyone understands the Polynesian society, cousins fall out now and again … our job is getting it back.”