Dozens of people are belived to have died in the Solomon Islands after an underwater earthquake propelled a 10m (33ft) tsunami into coastal villages, washing away entire communities in one of the world's poorest and most remote nations.

A state of emergency was declared yesterday by Manasseh Sogavare, the Prime Minister, as aftershocks from the magnitude 8.0 earthquake shook the country’s Western province and rescue teams struggled to reach thousands of refugees sleeping out in the open.

The tsunami alert triggered evacuations across the Pacific.

In Australia officials closed East coast beaches, warned fishing boats to come in and cancelled ferry services in Sydney Harbour. Residents left homes, hospitals and schools and fled to higher ground.

Outside Cairns there were traffic jams as panicked locals – even those living inland and well above sea level – fled the city while others abandoned their cars in lowlying areas. Gary Schofield, of Cairns disaster management group, said that authorities knew the tsunami was unlikely to strike the region’s shore but were unable to stop the panic.

Seismologists issued a warning that there was a 50 per cent chance of a second equally powerful earthquake striking anything between a few hours and several weeks after the first. The Solomon Islands have suffered six “double earthquakes” in the past 90 years.

No wave was detected in Papua New Gunea, the Solomons' nearest neighbour, allaying fears that there would be a repeat of the 2004 Boxing Day tsunami, which killed 280,000 people across the Indian Ocean. There were no reports of damage from elsewhere.

Survivors said the earthquake, which struck at 7.35am yesterday just as the Solomon Islands’ children were making their way to school, destroyed buildings, including the hospital, in the provincial town of Gizo and was followed almost immediately by huge waves.

One small offshore island was said to have been entirely washed away, leaving corpses floating in the sea. “It’s a catastrophe,” Dorothy Parkinson said on Australian television from her home in Gizo, a town of 7,000 people.

“[There was] very little warning. It was just a noise like an underground explosion and the next thing it just... began rocking the whole hill. The wave came almost instantaneously. Everything that was standing is flattened. It threw a piano to the ground. Everything on the ground is smashed.”

Danny Kennedy, who owns a diving shop in Gizo, said: “There are boats in the middle of the road, buildings have completely collapsed and fallen down. There are reports that some villages were completely washed away. Sasamungga is quite a big village... It was reported that 300 houses were destroyed in that village alone.”

Alex Lokopio, the leader of Western province, said: “All of a sudden the sea was rising up so all the people ran up the hill. What we desperately need now is water, tents and food because almost 4,000 people are now living on the hill at Gizo.”

The Australian Government pledged $2 million (£825,000) in emergency aid and said that helicopters already in the Solomons as part of a multinational security mission had been made available.

A police spokesman told The Times that a makeshift clinic had been set up on high ground for most of the Gizo injured, although three of the casualties had been flown to hospital in the capital, Honiara.

“We’re doing our best to get supplies to the makeshift hospital,” the spokesman said. “We are struggling with communication to the smaller islands at the moment and it’s very hard at this stage to know how many have been wounded.”

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