At least eight people have been confirmed dead after a cyclone devastated Vanuatu, according to a senior aid agency official.

Another 20 had been confirmed injured, Save the Children's country director Tom Skirrow told Reuters by telephone from Port Vila, saying the figure came from the country's National Disaster Management Office and was based on reports from hospitals and paramedic services.

The powerful storm tore off roofs, uprooted trees. Winds up 340 kph left the country cut off, with little power, poor communications and a looming threat of hunger and thirst.

350 Pacific / Facebook DEBRIS: One of many houses that lost their roofs in Vanuatu after the cyclone.

Unconfirmed reports said the number of dead could run into dozens but aid workers said it would be days or weeks before the full impact was known.

'It felt like the world was going to end," said Alice Clements, a spokeswoman for the UN Children's Fund (UNICEF).

"It's like a bomb has gone off in the centre of the town. There is no power. There is no water."

1 of 28 UNICEF A woman who is past her due date to deliver her baby faces a situation where she has no access to water, food, power and shelter as a result of storm damage in in Malapoa, on the outskirts of the capital Port Vila in Vanuatu. 2 of 28 UNICEF A family carries their belongings on the outskirts of Port Vila. 3 of 28 NZDF Scenes of devastation in the area around Port Vila in Vanuatu. A local villager who was injured when hit by masonry caused by a shipping container breaking through a concrete wall. 4 of 28 NZDF Scenes of devastation in the area around Port Vila in Vanuatu. Villagers set about the task of clearing away the debris that once was their local community centre. 5 of 28 UNICEF Residents contend with storm damage in Mele village, on the outskirts of the capital Port Vila. 6 of 28 NZDF Scenes of devastation in the area around Port Vila in Vanuatu. Children stand around the remains of a local community centre destroyed in the cyclone. 7 of 28 NZDF Scenes of devastation in the area around Port Vila in Vanuatu. Damage to a building at a local school that had been used as an emergency evacuation centre during the cyclone. 8 of 28 NZDF Scenes of devastation in the area around Port Vila in Vanuatu. 9 of 28 NZDF Scenes of devastation in the area around Port Vila in Vanuatu. 10 of 28 UNICEF Teouma bridge is affected by storm damage in Vanuatu. 11 of 28 UNICEF Residents contend with storm damage in Mele village, on the outskirts of the capital Port Vila in Vanuatu. Tens of thousands of children are in urgent need of help. 12 of 28 UNICEF Residents contend with storm damage in Mele village, on the outskirts of the capital Port Vila in Vanuatu. 13 of 28 UNICEF Residents contend with storm damage in Mele village in Vanuatu. 14 of 28 A large tree uprooted by Cyclone Pam lies on a street near a prison in Port Vila 15 of 28 KRIS PARAS/Reuters Local residents stand outside their homes on a road littered with debris after Cyclone Pam hit Port Vila 16 of 28 A woman carrying a baby stands with children outside homes damaged by Cyclone Pam, on a street surrounded by debris in Port Vila. 17 of 28 Catherine de Croy "It's just devastating, and this is by no means the worst of it," says Catherine de Croy from Port Vila. 18 of 28 Catherine de Croy The cyclone hitting the Vanuatu capital, Port Vila. 19 of 28 Catherine de Croy The Vanuatu capital, Port Vila. 20 of 28 Catherine de Croy These photos were sent in my Catherine de Croy from Port Vila. She was evacuated to the capital from a beach resort. 21 of 28 Reuters Local residents look through the remains of a small shelter in Port Vila. 22 of 28 Reuters Local residents walk past debris as a wave breaks nearby in Port Vila. 23 of 28 GRAHAM CRUMB/Humans of Vanuatu "Desperately trying to hold the roof down. He lost the corner of the building during the night, and was desperate not to lose the rest of it." 24 of 28 GRAHAM CRUMB/Humans of Vanuatu Police patrolling in downtown Port Vila on Saturday. 25 of 28 Graham Crumb/UNICEF The damage in Port Vila after Cyclone Pam hit Vanuatu. 26 of 28 UNICEF The damage in Port Vila after Cyclone Pam hit Vanuatu. 27 of 28 UNICEF The damage in Port Vila after Cyclone Pam hit Vanuatu. 28 of 28 UNICEF The damage in Port Vila after Cyclone Pam hit Vanuatu.

Tom Skirrow, country director for the Save the Children aid group, said Vanuatu's National Disaster Management Office had confirmed eight dead and 20 injured. He said he expected those figures to rise substantially.Aid workers in Papua New Guinea said at least one person had been killed by the storm there.

Satellite photographs showed the storm covering virtually all of Vanuatu, a sprawling country of 83 islands and 260,000 people 2,000 km northeast of the Australian city of Brisbane.

As relief organisations scramble to assist cyclone-ravaged Vanuatu, Super Tropical Cyclone Pam looks to be one of the worst disasters to have ever hit the Pacific, a United Nations agency says.

Nasa Nasa satellite imagery shows the eye of the category 5 cyclone just northwest of the island of Aneityum.

UNICEF spokeswoman Alice Clements said from Port Vila on Saturday the full force of Pam was "dramatically worse" than had been initially predicted. Port Vila, on Efate's west coast, was reported to be without power or running water, with debris lining the streets.

"This will most certainly be a catastrophe for the people of Vanuatu," she said.

"I saw the sliding doors from my three-storey hotel room completely blow away - it was terrifying."

iCyclone / Facebook A "provocative" forecast by Fiji's meteorological service, right, shows Cyclone Pam passing by the North Island as a Category 4 storm. The official forecast by the Joint Typhoon Warning Center, left, has Pam passing further from NZ.

There were also unconfirmed reports of casualties from the outer islands.

UNICEF New Zealand executive director Vivien Maidaborn said: "While it is too early to say for certain, early reports are indicating that this weather disaster could potentially be one of the worst in Pacific history.

"The sheer force of the storm combined with communities just not set up to withstand it, could have devastating results for thousands across the region."

MetService Latest Severe Weather Warning from the MetService.

The agency was working with the National Disaster Management offices in Vanuatu, Fiji and the Solomon Islands to offer support, particularly in the areas of water, sanitation and hygiene, nutrition, health, education and protection.

"We currently have our UNICEF children's emergency fund open and we will remain in close contact with Pacific governments in order to provide additional support should it be called upon," Maidaborn said.

The cyclone scored a direct hit on the islands of Tanna, Erromango and Aneityum, and grazed the east coast of Efate.

meteo.gov.vu A forecast map issued at 9.11am NZ time shows the path of Cyclone Pam.

SEASONAL WORKERS IN NZ "DESPERATE FOR INFORMATION"

More than 650 people from Vanuatu resident in New Zealand are being looked after by a co-operative which provides seasonal workers for the horticulture and viticulture industries.

"We spoke with our people in Vanuatu last night and they were safe and well," Seasonal Solutions chief executive Greg Watson said.

"They had spent the last couple of days boarding up their houses and the office, and had taken their families inland to stay with relatives. It's the workers here in New Zealand who are desperate for information, and we are doing everything we can to support them."

Seasonal Solutions has established a fund to allow its members to provide further financial support to the workers and their families.

Some workers have already said they wished to return home.

"But with no flights running currently, and the only likelihood of any flights in the next few days being aid flights, all they can do is sit tight and wait. It is a very stressful time for these men."

Each year the seasonal workers from Vanuatu spend up to seven months in New Zealand between October and May.

"UNBELIEVABLE DESTRUCTION"

From Vanuatu, the Australian Red Cross tweeted that workers on the ground have reported "unbelievable destruction".

"We're extremely concerned for safety and well-being of tens of thousands of people across Vanuatu."

"Moments like these…our efforts are put to the test," local Red Cross CEO Jacqueline de Gailande said.

The Australian Government had arranged to do a flyover as soon as the weather allowed.

The New Zealand Air Force also had a C-130 plane to be deployed tomorrow morning, which would be used to transport supplies such as food, water, 200 first aid kits and 1300 tarpaulin.

The death toll was still uncertain but widespread casualties were feared. One person was confirmed dead in Papua New Guinea, where the storm passed earlier, Reuters reported.

WHOLE VILLAGES FLATTENED

Chloe Morrison, a World Vision emergency communications officer who is in Port Vila, told The Associated Press that the capital's streets were littered with roofs blown from homes, uprooted trees and downed power lines. She said she's hearing reports of entire villages being destroyed in more remote areas.

She said there is no power or running water in the capital and that communication remains unreliable.

"It's still really quite dangerous outside. Most people are still hunkering down," she said. "The damage is quite extensive in Port Vila but there are so many more vulnerable islands. I can't even imagine what it's like in those vulnerable communities."

The New Zealand High Commission in Port Vila, which is supposed to be cyclone-proof, had been been damaged "very badly", said Red Cross Pacific regional head Aurelia Balpe from in Fij.

Sune Gudnitz, the regional head of the UN Office for the Coordination of Humanitarian Affairs, told Reuters from Fiji that Vanuatu was vulnerable because of its position in the middle of the ocean.

"We fear the worst," he said. "It is possible that there will be a death toll that could be high. I can't give any numbers. I think it is a well-grounded fear."

Earlier on Saturday the eastern eye of the storm passed directly over the island of Tanna - population 30,000 - battering it with catastrophic wind gusts of 300kmh winds, FiJi's NaDraki Weather reported.

The lightly populated islands of Erromango and Aneityum - population about 3000 total - had taken a direct hit from the storm, which had also severely lashed the east coast of the island of Efate.

"Shutters blown away and trees downed. And we are indescribably lucky compared to most," wrote the administrator of Humans of Vanuatu on his Facebook page.

At midday, NZ time, the eye of the storm was moving south of Aneityum, into the ocean between Vanuatu and New Zealand, although the southern Vanuatu islands would still be experiencing gale force winds.

The storm had missed Fiji and Tuvalu and was expected to diminish in power as it moves south - but still should cause severe gales and rain on the North Island late Sunday and Monday, along with extremely large seas about the east coast.

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Unicef spokesperson Alice Clements told Radio New Zealand the storm had gone on for longer than expected.

"It was 15-30 minutes of absolute terror for everybody in this country."

Others described their fear on social media.

"Just got a text from a friend an hour ago in Malapoa, his roof has gone is being flooded and is burying himself in the mud under the foundations to try and stay put," wrote Megan William on Facebook.

"Folks, I'll be honest. It's really bad out there," Humans of Vanuatu wrote at the height of the storm. "The wind is howling with a deep roar that just doesn't let up. Anyone not in shelter now is in mortal danger. Frankly, I don't think our country will make it through this without some deep scars."

"We have family that are hiding out in the main Cathedral in Port Vila. We last heard from them at midnight Vila time. They said the wind was really really strong and that water was coming inside. They said they thought they were safe there though," wrote Katrina Meredith on Facebook.

'SIGNIFICANT EVENT'

The Category 5 storm was expected to weaken but still hit New Zealand's North Island as a "significant event" on Monday and Tuesday.

In New Caledonia, the islands of Ouvea, Lifou, Tadine were also under a cyclone warning and were experiencing high winds - but the storm was expected to miss them as it churned southeast.

In New Zealand, around 200mm of rain was expected to accumulate Sunday and Monday in the ranges of Gisborne, northern Hawke's Bay and eastern Bay of Plenty, with lesser amounts near the coast.

"Rivers and streams in these areas will rise rapidly and localised surface flooding and slips are likely as well as hazardous driving conditions," MetService's warning said.

Severe southeast gales were likely about Gisborne and Bay of Plenty on Monday, with gusts of 120km in places, and 160kmh or more about the eastern Bay of Plenty.

"Winds of this strength are likely to cause damage to trees and powerlines and could lift roofs and make for hazardous driving conditons."

Gisborne Civil Defence emergency manager Richard Steele said an emergency operation centre was being established for the region and would likely be fully activated around 5am on Monday.

Rotary New Zealand said it had 600 emergency response kits on standby for immediate dispatch to affected areas in Vanuatu.

Disaster response practitioners were also on standby to go to Vanuatu to assist.

The charity was appealing for funds to help families rebuild their homes and re-establish vegetable gardens in addition to health and education issues.

-Stuff and agencies