President calls for global help as aid workers tell of fierce impact and Australia and New Zealand prepare to mount relief efforts

Teams of rescue workers were on Saturday night racing to reach the remote Pacific island chain of Vanuatu, which has been devastated by one of the most powerful cyclones ever recorded. More than 40 people are reported to have been killed so far after winds reaching 200mph destroyed homes, roads, power supplies and harbours. The death toll is expected to rise well beyond that figure.



Some reports said entire villages had been destroyed in remote areas. “Homes have been blown to pieces, and even evacuation shelters, where people had sought refuge, have been flooded and left exposed to the cyclone,” said Charlie Damon of Care International.



In some places, islanders crowded into caves and other makeshift shelters for safety. “I can say that for anybody who wasn’t in a secure shelter last night, it would have been a very, very tough time,” said Chloe Morrison of World Vision, who is based in the capital, Port Vila.



UN secretary general Ban Ki-moon said the impact of the disaster was not yet clear, but he feared the damage and destruction were widespread. The UN was preparing to deploy emergency response units. Britain pledged up to £2m towards relief efforts – the Department for International Development said up to £1m would be available immediately with the same sum from the UK’s rapid response ­facility.



Facebook Twitter Pinterest A Nasa satellite image of cyclone Pam shows the eye of the storm just east of Vanuatu. Photograph: Goddard MODIS Rapid Response Team / NASA / HANDOUT/EPA

Alex Mathieson, Oxfam’s former director of Vanuatu, who lived there for four years and now works for the charity in Melbourne, Australia, said a British woman is among a number of his friends he is anxiously waiting to hear from. “We’re concerned for her and a couple of other friends we haven’t been able to get hold of,” he said. “We’re hoping for the best from those we haven’t heard from. Me and my colleagues have watched with a sense of horror and ­helplessness.”



The Foreign Office said it is working to establish whether any British nationals have been affected by the disaster.



Cyclone Pam had not been forecast to hit Vanuatu directly, but a westward change of course put the islands in its path early on Saturday. Unicef spokeswoman Alice Clements said the cyclone was “15 to 30 minutes of absolute terror” for “everybody in this country”.



Save the Children’s Vanuatu director, Tom Skirrow, described its aftermath as a scene of complete devastation: “Houses are destroyed, trees are down, roads are blocked and people are wandering the streets looking for help.”



New Zealand pledged NZ$1m (about £500,000) to help with relief efforts, while Australia said it was preparing to send a crisis response team if needed. “There are destructive winds, rain, flooding, landslides, sea surges and very rough seas, and the storm is exceedingly destructive there,” said the foreign minister, Julie Bishop. “We stand ready to assist.”



The UN said there were unconfirmed reports of 44 deaths in Vanuatu’s north-eastern islands after Pam veered from its expected track. However, that number is expected to rise significantly as reports come in from outlying areas. Vanuatu has a population of about 267,000, spread over 83 islands, with some 47,000 people living in Port Vila.



“We anticipate that there will be higher numbers [of casualties] on remote islands, because they have less sophisticated shelter,” said Oxfam’s Vanuatu director, Colin Collett van Rooyen. “But we have no indication of what’s happening there because we have no communications to the islands … there has been significant destruction of homes in some areas. We have no power or running water and are still not able to move around freely,” he added. “The scale of this disaster is unprecedented in this country, and the people of Vanuatu are going to need a lot of help to rebuild their homes and their lives.”



David Cameron (@David_Cameron) My thoughts are with those affected by #CyclonePam. We have offered immediate support to Vanuatu. http://t.co/XlVG5BwE83

Vanuatu’s president, Baldwin Lonsdale, who had been attending a conference on disaster risk in Japan, issued an emotional appeal for aid. “I stand to appeal on behalf of the government and the people of Vanuatu that the global community give a lending hand in responding to these very current calamities that have struck us,” he said.



The island nation, which lies about a quarter of the way from Australia to Hawaii, has repeatedly warned that it is suffering devastating effects from climate change as its coastal areas are washed away, forcing people to resettle on higher ground. Port Vila is considered to be the city most exposed to natural disasters in the world: as well as cyclones, it faces risks of earthquakes, tsunamis and floods.



Weather forecasters said cyclone Pam had started to weaken as it moved away from Vanuatu and would pass between Fiji and New Caledonia before brushing the North Island of New Zealand.

Facebook Twitter Pinterest In this image provided by Unicef Pacific, people walk past debris is scattered on a street in Port Vila. Photograph: AP

A UN report this week found that economic losses over the past 45 years in the Asia Pacific from natural disasters totalled $1.15tn, with a loss of more than two million lives. Vanuatu was the country most at risk in the world from natural disasters, ahead of Tonga, the Philippines, Japan and Costa Rica, the document said.