A gale warning remains in force for the northern Cook Islands.
A tropical depression is near the atolls of Rakahanga, Manihiki, Penryhn and Suwarrow.
The system is moving south at 9 kilometres an hour, with winds of 55 kilometres an hour at its centre.
Forecasters are warning that the northern atolls can expect damaging gale force winds, periods of heavy rain and squally thunderstorms, and high seas.
The depression could develop into a tropical cyclone.