PORT VILA – Vanuatu is warning it faces imminent food shortages as accounts emerge of huge damage to a large outer island, days after one of the fiercest cyclones on record pummelled the Pacific archipelago.

Relief agencies said conditions were among the most challenging they have faced, with concerns mounting that disease and a lack of clean water could add to the current death toll.

There are fears the toll will also rise once officials are able reach outer islands to inspect the damage there.

Communications were still down to many of Vanuatu’s 80 other islands, most only accessible by boat, and prime minister Joe Natuman said it would be at least a week before authorities had a better sense of the destruction.

President Baldwin Lonsdale has appealed for the world to help and leaders, including from Australia, New Zealand, Britain, France and the EU have pledged aid.

The scale of the disaster became clearer with the first teams of aid workers reaching Tanna island, home to 30,000 people.

It is some 200 kilometres south of the capital Port Vila, itself badly damaged.

“Someone said it was like a giant whipper-snipper had gone across and smashed thousands and thousands of strong, hardwood trees – just bent, smashed like match sticks,” Joe Lowry from the International Organisation for Migration said.

“Every solid structure had been quite badly damaged. We were the first people they had seen since the storm. They wanted to know what was happening in the outside world.

“They reported that they had about a week’s supply of fresh water left and their food stocks had been damaged and were running low.”

CARE Australia’s Tom Perry said the destruction was widespread.

“The impression they got from their initial observations was that the damage is significantly worse than Port Vila,” he said.

He said that the hospital on Tanna was functioning but did not have a roof.

Natuman said while initial assessors had been able to enter the eastern and western parts of the island chain, northern and southern areas were still largely inaccessible.

“It’ll be at least a week or two. Right now we are sending teams to do ground assessments to see how many people are homeless,” he said.

Benjamin Shing, a spokesman for President Lonsdale’s office, said survivors would quickly run out of food.

“The first week we are relying on the fact that the food crops and the gardens are still edible and they can be used for the first week, but after the first week we’ll need to get some rations on the ground,” he told the ABC.

With crops wiped out, Shing feared the worst for a country that largely relies on subsistence farming, warning “there might be a lot of fatalities”.

The UN Office for the Coordination of Humanitarian Affairs said in a situation report “there are 24 confirmed fatalities” across Vanuatu so far and some 30 injured. But that figure was later revised down by the UN to 11.

Perry said at least five of the dead were from Tanna, adding that “food running out is of great concern” for CARE Australia.

Local woman Sale Chilia said residents living in Mele, a village two kilometres south of Port Vila, were starting to worry about where they could find their next meal.

“We only have the leftovers now,” she said.

In Port Vila, access to water and electricity was partially restored after the storm brought down an estimated 80 per cent of power lines and damaged most homes.

Some stores began reopening, but entire neighbourhoods remained without power as locals struggled to rebuild their homes.

In the capital, leaves and branches lined the streets while residents began clearing metal roof sheeting from the roads around their houses and used machetes to hack through fallen trees.

Personal belongings, household items, mattresses and clothes were spread out on the ground and hung on washing lines as people dried them out.

Samuel Toara, 25, thought he was going to die when the storm barrelled ashore.

He sheltered in the pitch black with two other young men as the tempest roared past his home.

“It was very hard,” he said. “The cyclone sounded like a big plane flying very low.”

As heavy rain pounded his house, made of corrugated metal and timber, part of the roof blew off.

“The rain and wind was like white smoke and it flooded up to my knee,” he said.

“But I told the boys, don’t worry about the water. As long as we survive.”

The UN said there were at least 3300 people sheltering in 37 evacuation centres around the country.

UNICEF estimated that 60,000 children have been affected by the cyclone and virtually all schools were closed.

Emergency specialist Mioh Nemoto said there was concern about what they would eat.

“Food security is likely to be a continual problem and we need to start thinking now about how children will stay well fed,” he said.