No details have been released, but analysts and environmentalists fear it will pave the way for closer security ties and the start of deep-sea mining.

But the proposed pact has shaken decades-old ties between the Cook Islands and New Zealand, neighbours that are set to mark 60 years of a free association agreement in 2025. That agreement has long given New Zealand influence over the Cook Islands, especially over its foreign policy.

China says a visit this week by the Cook Islands' prime minister to Beijing was not meant to conspire against anyone in the South Pacific, despite the trip stirring up a diplomatic spat between the tiny nation and its chief benefactor,

The Cook Islands said on Saturday that it signed a comprehensive strategic partnership deal with China - a move expected to raise concerns in New Zealand with which it has constitutional ties. The deal was signed by Cook Islands Prime Minister Mark Brown during a visit to Beijing.