Cyclone Victor is causing gale-force winds on Palmerston in the Cook Islands and is expected to intensify into a Category 4 on Monday.
The atoll has been on high alert as the cyclone, upgraded to category 3 on Sunday and centred several hundred kilometres away, moved slowly towards it.
Winds close to the centre are about 115 km/h. The Fiji Meteorological Service says the cyclone is intensifying and the wind strength will increase to 150 km/h.
A gale warning is in place for the Southern Cooks and there will be showers and possibly thunderstorms.
An observer at the Cook Islands Meteorological Service, Manea Mareteapu, said the cyclone was moving at two knots, which is slow, indicating that it is still intensifying, and it would be a category 4 by Monday.
Palmerston resident Will Rowe said wind was already gusting up to 120 km/h on the atoll and it was unsafe to be outside.
"The seas are incredibly high coming from the north, the lagoon is boiling like a cauldron and we have fallen fronds and coconuts and other debris right across the island at present, so it's getting to the point now where it's going to become unsafe for people to leave their homes."
Mr. Rowe said authorities had taken action and people were prepared with supplies.
"In terms of preparations, everyone's sort of got a go-pack so to speak, with food and water and everything, medicine that they require. The Palmerston Island Administration has been absolutely fantastic in assisting households on the northern side to evacuate which has already been done. The Palmerston Island people are very resourceful, hardy people and have been through all this before."
Palmerston Island Administration executive director Arthur Neale said the island's 59 residents had been preparing for the past few days and those on the north of the island close to the shore have moved to homes further inland.
He says the normally placid lagoon was something to behold.
"Yeah you look out and it's just like a churning washing machine, it's just constant white horses."
Rough seas had already eroded as much as 10 feet of the shoreline in some places, he said
Mr Neale said boats had been moved to the centre of the 1.2 square kilometre main island, and houses and public buildings had been secured ahead of tonight's expected worsening conditions.
"As a low-lying island, you do what you can do. We've had some slight flooding in the lower areas, we've also had a bit of erosion."
However, Mr Neale said the cyclone's rain was welcome on the drought-stricken island, where there had not been any rainfall for two months.
"We welcome the rain, that's for sure. We're in the middle of a drought with the El Niño. Our last rain was when cyclone Tuni came by on the 13th of November."
The southern Cook Islands are expected to avoid a close encounter with Victor as it moves southwest between Rarotonga and Niue. However, Arona Ngari warns that cyclone forecasts are vulnerable to change and people should continue to monitor forecasts.