Most of the victims of the Burma cyclone were overwhelmed by a 12ft moving wall of water that bore down on their lowlying villages at the mouth of the Irrawaddy river delta.

In a rare press conference, members of the Burmese junta today gave the most detailed description to date of the disaster that killed at least 22,000 people at the weekend, and left a further 41,000 missing, according to Burmese state radio.

“More deaths were caused by the tidal wave than the storm itself,” said Maung Maung Swe, Burma's Minister for Relief and Resettlement, at a news conference in the rubble-strewn city of Rangoon, where food and water supplies are running low.

“The wave was up to 12ft (3.5 metres) high and it swept away and inundated half the houses in low-lying villages. They did not have anywhere to flee.”

He confirmed that most of the town of Bogalay had been washed away. “Ninety-five percent of the houses in Bogalay were destroyed,” he said. “Many people were killed in a 12ft tidal wave."

Nasa satellite images showed virtually the entire coastal plain of Burma is now lying under water. With roads washed away and phone lines down, so far eyewitness reports of conditions in the Irrawaddy delta - home to nearly half Burma's 53 million population - have come mainly from aid workers who have flown over by helicopter.

They report corpses littered across the ruined rice paddy fields, and desperate survivors preparing to spend a fourth night without shelter or clean water.

The Christian relief organisation World Vision, one of the few international agencies allowed to work inside Burma, said its teams had flown over the most affected regions and witnessed horrific scenes on the ground.

“They saw the dead bodies from the helicopters, so it’s quite overwhelming,” said Kyi Minn, a World Vision adviser based in Rangoon.

“The impact of the disaster could be worse than the (2004 Asian) tsunami because it is compounded by the limited availability of resources on top of the transport constraints.”

Images from Burmese state television showed large trees and electricity poles sprawled across roads, and roofless houses ringed by water in the delta, once a lacework of paddy fields and canals regarded as Myanmar’s rice bowl. The salt water will have destroyed the rice fields for years to come.

Even in delta villages that managed to withstand the worst of the winds, food and water is already running low.

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