UN humanitarian affairs chief, John Holmes, has secured a visa for cyclone-hit Burma and will arrive in Rangoon for talks on relief aid Sunday, a spokeswoman said.

"He will be flying Saturday and he will be in Burma Sunday," Michele Montas told reporters.

Holmes is being sent to Burma by UN chief Ban Ki-moon to push its military leaders to open the country up more to international assistance.

'aid crisis'

Aid is still only trickling in as Burma's ruling junta has rejected requests by numerous foreign and multinational aid teams to enter and help distribute relief supplies to hundreds of thousands of famine and disease-threatened survivors of the deadly storm.

Mr Ban called the junta's response to the disaster "unacceptably slow".

Burma said on Friday more than 133,000 people were dead or missing in the cyclone disaster, nearly doubling the official toll two weeks after the storm left the country's rice-growing south in ruins.

The announcement came as Burma's military rulers, welcoming aid from abroad but suspicious of the outside world, again rejected calls to let foreign experts direct the massive relief effort for 2.5 million needy survivors.

'climbing death toll'

State television put the latest toll at 77,738 dead and 55,917 missing - numbers close to estimates by international aid groups in recent days as the full scope of the destruction in the Irrawaddy Delta becomes known.

The news bulletin said the government had not been able to confirm the increase earlier due to the widespread damage as well as subsequent heavy rains, which have deepened the misery in one of the world's poorest nations.

It said 19,359 people were injured. Among government personnel, there were 159 dead, 58 missing and four injured. No other details were given.

The junta has insisted it can manage the catastrophe alone, despite urgent international pleas to open up their doors and avert a second wave of death among desperate victims short of food, water, shelter and medical care.

But while the generals have accepted hundreds of tonnes of relief supplies - from high-tech foodstuffs used in famine regions to the most basic needs like fresh water - they have rebuffed foreign disaster management experts.

Instead, the secretive regime has thrown a tightening ring of security around Rangoon, blocking aid workers, foreign diplomats and journalists from reaching cyclone-battered regions where millions need food and medicine.

New roadblocks manned by armed police have sprung up around Burma's largest city. Authorities at the checkpoints take down passport information and licence plate numbers and sometimes interrogate drivers and their foreign passengers before ordering them to return to Rangoon.

"A circle has been drawn around Yangon (Rangoon) and expats are confined there. While you are getting aid through, it's like getting it through a three-inch pipe, not a 30-inch pipe," says Tim Costello, president of the aid agency World Vision Australia, in Rangoon.

Louis Michel, the European Union's humanitarian aid commissioner, concluded a two-day visit on Friday but was unable to visit the delta - a main rice-growing region in the country.

He says that more than 100 doctors from neighbouring countries would go into the country on Saturday, and stressed that time was running out to prepare for the October rice harvest in the country.

"Time is life," he said in Bangkok after the trip.

He had previously warned that the country, once a rich British colony, is at risk of famine after Cyclone Nargis, which hit May 2-3, wiped out vast swathes of paddies and destroyed rice stocks.

Meanwhile, Western diplomats who declined to be named said the regime was taking them to the delta on Saturday, but had no further details about where they would be going.

"We're not expecting to be shown the real picture or be given any freedom to see what we'd like to see," one diplomat says.

'military rule'

The military, which has ruled Burma for nearly 50 years, keeps a tight rein on all aspects of life here - and Mr Michel says he had put a series of requests to authorities to ease the relief effort.

Among the requests, he said, was for local Burmese staff working for aid groups to be able to go back and forth freely into the disaster zone, rather than get individual permission from authorities.

"They are tempted to react positively to our requests," he says.

"But I feel also reluctance because the relationship between authorities and the international community (is) of course not very positive. So they are hesitant."

Burma's Southeast Asian neighbours meanwhile were gearing up for talks in Singapore on Monday aimed at convening a high-level donors meeting.

A UN source said a donor meeting would likely take place in Southeast Asia, probably Bangkok, with May 24 suggested as a possible date.