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.

China and the Cook Islands on Friday signed a comprehensive strategic partnership agreement, but the lack of transparency around the details has alarmed New Zealand, the South Pacific state’s closest democratic ally.

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.

Cook Islands officials yesterday said they had discussed seabed minerals research with China as the small Pacific island mulls deep-sea mining of its waters.

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 is willing to deepen mutual political trust with the Cook Islands, China's Premier Li Qiang said during a meeting with Cook Islands Prime Minister Mark Brown, China's national television broadcaster reported on Friday.