YANGON (AFP) - - Emergency aid trickled into Myanmar where more than a million desperate cyclone survivors Thursday faced a grim battle against disease and starvation and a US diplomat said the death toll may top 100,000.

As pressure mounted on the reclusive junta to let in foreign aid agencies, haunted victims told how entire families were wiped out -- and how their own survival often depended on the branch of a tree.

Aid is slowly arriving, but not quickly enough nor in sufficient quantities to really help people in the stricken Irrawaddy delta who saw their villages ripped apart by Cyclone Nargis.

Authorities in Yangon raised the official death toll to nearly 23,000 late Wednesday, with state media saying more than 42,000 others were missing.

But a military official in the delta township of Labutta estimated 80,000 dead there alone, and many families told an AFP reporter who travelled to the area that most of their relatives had been killed.

"The storm came into our village," said a man in his 20s, "and a giant wave washed in, dragging everything into the sea.

"Houses collapsed, buildings collapsed, and people were swept away. I only survived by hanging on to a big tree." He said his wife and two children both died.

"The waves were so strong, they ripped off all my clothes. I was left naked hanging in a tree," said another teenager who escaped.

Around 5,000 square kilometres (1,930 square miles) remain underwater, and more than a million people need emergency relief, a UN spokesman said.

"The bottle-neck (in aid) is getting it out in the delta. That needs boats, helicopters, trucks," said Richard Horsey, a Bangkok-based spokesman with the United Nations Office for the Coordination of Humanitarian Affairs.

Shari Villarosa, US charge d'affaires in Yangon, said there could be more than 100,000 dead in the Irrawaddy delta region where 95 percent of buildings were reported to have disappeared.

Food prices in Myanmar, already one of the most impoverished nations in the world, have soared since the storm. One bag of rice now costs 40,000 kyats (35 dollars) in the commercial hub Yangon, up from 25,000 before.

Petrol on the black market, where most people obtain their fuel, has more than doubled to 11,000 kyats a gallon.

Frustrated aid agencies have said they are still being denied permission to enter Myanmar and use their experience and expertise to ensure the right aid gets to the neediest places as soon as possible.

"It should be a simple matter. It's not a matter of politics. It's a matter of a humanitarian crisis," US Secretary of State Condoleezza Rice said.

The military junta has promised that emergency foreign aid workers will be allowed in, but has yet to issue any visas.

"We need to encourage the authorities to move further and not to bludgeon them over the head," UN humanitarian chief John Holmes told the BBC.

He said 24 countries had offered specific help and another six unspecified aid, adding up to well over 30 million dollars with more to come.

An AFP reporter who reached Labutta said there was hardly any food or fresh water left there.

Witnesses said that Saturday's storm, packing winds of 190 kilometres (120 miles) per hour, had left the delta region submerged under six-metre (20-foot) waters higher than the tree-tops.

As the waters receded, countless corpses have been left rotting in the heat alongside the bloated carcasses of animals.

UN officials in Bangkok said the World Food Programme had been able to distribute some food aid in Yangon, while hundreds of tonnes of relief supplies have arrived from Thailand, China and India .

Further pressure on Myanmar's military junta came from the ASEAN group of Southeast Asian nations, whose secretary-general Surin Pitsuwan said the junta must let in foreign agencies "before it's too late."

The UN refugee agency said 22 tonnes of supplies were stuck at the border with Thailand, awaiting permission to enter.