YANGON, MYANMAR - Aid agencies rushed emergency food and water into Myanmar on Monday after a cyclone tore into the impoverished nation, killing more than 350 people and leaving hundreds of thousands homeless.

Despite the devastation wreaked by tropical cylone Nargis, the ruling junta vowed to press ahead with its controversial referendum this weekend on a new constitution, which critics say will entrench military rule.

Nargis left at least 351 dead after making landfall in southwestern Myanmar at the weekend, packing winds of 190 kilometres (120 miles) per hour, wrecking thousands of buildings and knocking out power lines, state media reported.

"I haven't seen anything like this in my whole life. It will take at least a month to return to normal," a 70-year-old man told AFP.

Several coastal villages southwest of Yangon were destroyed, according to a preliminary assessment by the International Federation of the Red Cross, its spokesman Michael Annear told AFP in Bangkok.

The villages in the Ayeyawaddy (Irrawaddy) delta bore the brunt of Nargis, which came in from the Bay of Bengal and combined with a sea surge.

State media said nearly 98,000 people were homeless on the delta's Haing Gyi island alone, which is home to a navy base.

Richard Horsey, a UN official in Bangkok, said that several hundreds of thousands of people had been left homeless and without drinking water.

"If we look at the emergency needs for shelter and drinking water, there are several hundred thousand people who will need urgent assistance," he told AFP.

UN agencies and other international aid groups met Monday in Bangkok to begin coordinating a response, and Annear said Red Cross teams in Myanmar were already distributing essential supplies.

"We're distributing supplies for those who need shelter, plastic sheeting to cover roofs, water purification tablets, we are currently procuring 5,000 litres of water, cooking items, bednets, blankets and clothes for those in most need," he said.

Hundreds of monks joined in efforts by residents, police and troops to clear blocked roads, while the homeless huddled under makeshift shelters at Buddhist temples.

"The government should do more and we need emergency assistance. Water is the main need for us. I haven't taken a bath for three days," a taxi driver told AFP.

Aid agencies said it would take days to get a full picture of the extent of the devastation.

The military government said Saturday's referendum on a new constitution intended to usher in democracy would go ahead, but with food prices tripling and water supplies cut, residents said they had more pressing problems.

"We don't want any democracy, we just want water now," a 30-year-old man said as he queued at a neighbour's well.

But the junta, based in the remote new capital of Naypyidaw, insisted "the entire people of the country are eagerly looking forward" to the referendum, the New Light of Myanmar newspaper reported.

The generals say it will pave the way for multiparty elections in 2010, but opponents say the charter will entrench military rule.

The country's infrastructure has been run into the ground by decades of mismanagement by the military, which has ruled since 1962.

Myanmar has also suffered more than a decade of US and European sanctions over the continuing detention of democracy leader Aung San Suu Kyi.

Sanctions were tightened after the junta's crackdown on mass protests last September left 31 people dead, according to UN figures.