The United Nations has confirmed 24 people are now confirmed dead after Cyclone Pam devastated Vanuatu, with the death toll expected to rise further.

Thousands of people are homeless in Vanuatu, following the cyclone, which is described as the biggest disaster to hit the country in living memory.

Aid is beginning to arrive in the country, much of which is without power, water or food.

Up to 90% of buildings have been destroyed in the capital, Port Villa.

Reporter Michael Morrah from TV3 New Zealand is in the capital.

He says eight people died in Port Villa, and another five people have been confirmed dead on Tanna Island, which was hardest hit:

Vanuatu's president says it's likely the state of emergency declared on the capital Port Vila - will be extended to other islands - once the extent of the damage has been assessed.

President Baldwin Londsdale says large parts of Port Vila have been decimated:

Officials say the death toll is likely to rise once communications are re-established with outlying islands.

"This is a very devastating cyclone in Vanuatu. I term it as a monster, a monster," Mr Lonsdale said. "It's a setback for the government and for the people of Vanuatu.

"After all the development that has taken place, all this development has been wiped out."

The president said even he has been unable to contact family members due to the widespread destruction caused by the 300km/h winds.

The cyclone levelled homes, smashed up boats, destroyed roads and bridges, and brought down power and phone lines. Thousands have been left homeless on the archipelago.

"We do not know if our families are safe or not. As the leader of the nation, my whole heart is for the people, the nation," he said.

Mr Lonsdale is preparing to return to Vanuatu from Sendai, in Japan, where he was attending a disaster conference when the cyclone struck.

Authorities are still struggling to determine the scale of devastation from the storm, which struck the islands early on Saturday local time.

Originally posted at 7.20am