UN humanitarian affairs chief John Holmes told reporters that there were now between 1.6-2.5 million people who were "severely affected" by Cyclone Nargis and urgently needed aid, up from a previous estimate of at least 1.5 million people.

Thai Prime Minister Samak Sundaravej said after a two-hour meeting in Yangon, where he urged his counterpart Thein Sein to ease visa rules for relief workers, that he was told Myanmar could "tackle the problem by themselves."

In New York, UN Secretary-General Ban Ki-moon, who has expressed frustration over the response by Myanmar's reclusive leaders, met key donor states and Asian powers to discuss "what kind of concrete measures we can do from now on."

"Even though the Myanmarese government has shown some sense of flexibility, at this time it is far, far too short," he said. "The magnitude of this situation requires much more mobilization of resources and aid workers."

Among those invited were the United States, Britain, France, Russia, China, India, Bangladesh, Australia and Japan.

TRICKLE OF AID

Nearly two weeks after the cyclone swept through the heavily populated Irrawaddy delta rice bowl, killing tens of thousands of people, foreign aid still amounts to little more than a trickle.

Myanmar, formerly called Burma, was once the world's biggest rice exporting country but more than 40 years of military rule have left it impoverished. The military junta has repeatedly crushed pro-democracy movements and tightly restricts visits by foreigners.

Samak told reporters in Bangkok that Myanmar's leaders had insisted that teams of foreign experts, who have been refused entry, were not needed.

"They are confident of dealing with the problem by themselves. There are no outbreaks of diseases, no starvation, no famine. They don't need experts, but are willing to get aid supplies from every country," Samak said.

Louis Michel, the top European Union aid official, disagreed. "There is a risk of water pollution. There is a risk of starvation because the storages of rice have been destroyed," he told reporters in Bangkok.

"We want to convince the authorities of our good faith. We are there for humanitarian reasons," he said. He threw cold water on suggestions from some European countries that foreign countries move unilaterally to bring in aid.

Adm. Timothy Keating, the commander of US forces in the Pacific, also rejected that idea. "We have absolutely no intention of forcefully providing relief supplies," he said in an interview with National Public Radio.

He said US flights of emergency aid would continue for the time being, even though Myanmar was refusing permission for US officials to monitor, or help with, distribution.

A senior US military official in Washington said there were signs that aid was stacking up at Yangon airport and said Washington was keen to get permission to fly helicopters to the worst-affected areas.

The official said there were reports that some 230 camps had been set up to house more than 230,000 displaced people. "They're springing up all over the place," he said. "The problem they have is a lack of water and sanitary facilities."

Officials said despite reports that some supplies were being stolen or diverted by the army, the humanitarian needs were so great that they would keep making deliveries -- while continuing to urge that US aid workers be granted visas.

ACCESS IS "CRITICAL"

World Food Program chief Josette Sheeran said in Washington her organization had so far reached 28,000 people.

"A critical issue now is access," she said. "Our flights are allowed to bring in some supplies, but far from enough - a massive effort is needed to save lives..." she told a US Senate hearing on the global food crisis.