Burma's junta seized two planeloads of critical aid sent by the UN for a multitude of hungry and homeless survivors of last week's devastating cyclone, forcing the world body to suspend further help.

"All of the food aid and equipment that we managed to get in has been confiscated," said Paul Risley, a spokesman of the World Food Program (WFP) in Bangkok.

He said the seized aid, including 38 tonnes of high-energy biscuits, arrived on two flights from Dhaka, Bangladesh, and Dubai, United Arab Emirates.

"It is being held by the government. We are waiting resolution of this matter," he said.

Meanwhile, more than 1 million people made homeless in last Saturday's cyclone waited for food, shelter and medicine. Many crammed into Buddhist monasteries or just camped out in the open.

Entire villages were submerged in the worst-hit Irrawaddy Delta, with bodies floating in salty water and children ripped from their parents' arms.

At least 62,000 people are dead or missing, state media reported, and aid groups warned that thousands of children may have been orphaned and the area is on the verge of a medical disaster.

The WFP had sent some aid on a scheduled Thai Airways cargo flight yesterday, which went through without a hitch. Another flight carrying Italian aid also came in yesterday.

But a bureaucratic mix-up led to the seizure when the two flights landed today, Risley said. Until it is freed, the UN will send no more aid, Risley said.

"For the time being, we have no choice but to end further efforts to bring critical needed food aid into Myanmar at this time," Risley said, using the junta's name for Burma.

The isolationist regime of this Southeast Asian nation has also refused to grant visas to foreign aid workers who could assess the extent of the disaster and manage the logistics.

"The frustration caused by what appears to be a paperwork delay is unprecedented in modern humanitarian relief efforts," Risley said.

"It's astonishing."

He said the WFP submitted 10 visa applications around the world, including six in Bangkok, but none has been approved.

"We strongly urge the government of Myanmar to process these visa applications as quickly as possible, including work over the weekend," he said.

Today, Japan said it will give aid worth $US10 million ($A10.6 million) through the UN to Burma, adding to the massive amounts of aid that has been pledged by foreign governments.

The junta said in a statement today it was grateful to the international community for its assistance - which has included 11 chartered planes loaded with aid supplies - but the best way to help was just to send in material rather than personnel.

One relief flight was sent back after landing in Rangoon yesterday because it carried a search-and-rescue team and media representatives who had not received permission to enter the country, the junta said. It did not give details, but said the plane had flown in from Qatar.

"Believe me the government will not allow outsiders to go into the devastated area," said Rangoon food shop owner Joseph Kyaw,

"The government only cares about its own stability. They don't care about the plight of the people," he said.

In neighbouring Thailand, tonnes of critical aid and experts are waiting to go in if the junta gives permission.

Among those waiting were members of the USAID Disaster Assistance Response Team. Air Force transport planes and helicopters packed with supplies also sat waiting for a green light to enter Burma.

It is not clear how much of the aid that has reached Burma has been delivered to the victims in the Irrawaddy Delta.

The UN estimates 1.5 million people have been "severely affected" and voiced "significant concern" about the disposal of dead bodies.

According to state media, 22,997 people died and 42,019 are missing from Cyclone Nargis, which hit the country's Irrawaddy Delta last Saturday.

Shari Villarosa, who heads the United States Embassy in Rangoon, said the number of dead could eventually exceed 100,000 because of illnesses.

By snubbing the US offer to help cyclone victims, the junta has refused to take advantage of Washington's enormous ability to deliver aid quickly, which was evident during the 2004 Indian Ocean tsunami that killed 230,000 people in a dozen nations.

With roads in the Irrawaddy Delta washed out and the infrastructure in shambles, large swaths of the region are accessible only by air, something few other countries are equipped to handle as well as the US

Thai Prime Minister Samak Sundaravej told reporters today that he will try to go to Burma on Sunday to persuade the junta to accept US help.

But the junta told Samak his Burma counterpart is too busy to meet with him, said a Thai army general, speaking on condition of anonymity because he is not authorised to speak to the media.