Wellington: An extremely powerful cyclone blew over islands in the Pacific's Vanuatu archipelago late on Friday after a westward change of course put populated areas directly in the path of its destructive 270 kilometer- (168 mile-) per-hour winds, according to relief workers.

The U.N. Office for the Coordination of Humanitarian Affairs said in a release there were unconfirmed reports of deaths in Vanuatu's northeastern islands after Cyclone Pam moved off its expected track.

The Category 5 cyclone had average wind speeds of 250 kph to 270 kph, with gusts up to 340 kph, according to the office. It said the periphery of the eye of the storm had passed over islands that are home to several thousand people and was expected to hit or come close to the island of Efate, home to the capital, Port Vila.

Located about a quarter of the way from Australia to Hawaii, Vanuatu has a population of 267,000 spread over 65 islands. About 47,000 people live in the capital. Vanuatu had earlier issued a red alert to its residents, urging them to take shelter from Pam.

Authorities said they feared the cyclone would destroy homes as well as cause landslides and severe coastal flooding. The cyclone has already destroyed some homes and caused damage to other Pacific islands including Kiribati and the Solomon Islands.

David Gibson, acting director of the Vanuatu meteorology and geo-hazards department, said the winds could cause severe damage to the nation's buildings.

Alice Clements, a spokeswoman for relief agency UNICEF who is in Port Vila, said earlier on Friday the capital was like a ghost town as people took shelter. She said the pelting rain was blown horizontally by the wind.

"The weather has been getting progressively worse for the last two-and-a-half days," she said. "They've put the deck chairs at the hotel I'm staying at into the swimming pool to stop them blowing away. It's quite surreal."

She said many people in Vanuatu live in flimsy shelters, especially those on the more remote outer islands. She said those people are extremely vulnerable. She said she expects a huge cleanup and urgent medical needs after the storm passes.

Clements also said large seas had caused significant flooding in remote and low-lying Kiribati, local media reported several homes and a school classroom were destroyed and crops were flooded.

Authorities in New Zealand are preparing for the storm, which is forecast to pass north of the country on Sunday and Monday.