Cyclone Olaf, which earlier today battered American Samoa's eastern Manu'a Islands, is expected to bring damaging gale force winds to Palmerston Island, the most northern of the Cook Islands, within the next 24 to 36 hours.
The Cyclone at its centre currently has winds of 213 kilometres.
These are expected to drop to 190 kilometres within the next 24 hours.
The Fiji Met Service says Palmerston can expect squally thunderstoms and seas becoming rough to very rough with damaging heavy swells.
It is predicting winds of up to 90 kilometres an hour for the rest of the southern Cooks group by tomorrow night.
Meanwhile a New Zealand Orion has located two boats missing off Samoa and arrangements are being made to help the injured crew.
The Orion is searching for two other vessels known to be in distress, as well as a life raft containing six people who abandoned their fishing boat last night.
The Orion will refuel in Apia this evening.
As well, the US Coastguard has just found an American registered fishing vessel to the east of American Samoa, which had also sent out a distress beacon.