Supplies are scarce in many areas of southern Burma
Countries sending cyclone aid to Burma must monitor it closely to stop the military regime seizing supplies, a leading rights group has said.
Human Rights Watch said aid could not simply be left at Rangoon airport as it would not necessarily reach victims.
Burma's state media have raised the official death toll to 43,318 with 27,838 missing, AFP news agency said.
The regime is stopping most foreign aid workers already there from leaving Rangoon to go to affected areas.
More than 10 days after Cyclone Nargis struck the Irrawaddy delta, the BBC's Natalia Antelava, who reached the area, says it is still completely cut off from the outside world and there is little evidence of things getting better.
It is not just capacity to help that the Burmese government seems to lack, it is also the political will to save their own people
In an apparent concession to international pressure, the generals say they will allow 160 foreign aid workers into the country, as well as an emergency relief team from the Association of South East Asian Nations (Asean).
But it was unclear whether the workers - from countries including Thailand, China, India, Bangladesh - would be allowed out of Rangoon into the stricken delta region, where help is most urgently needed.
Aid agencies say far more boats and trucks are needed to get the supplies to the communities that need them most - and far more expert personnel.
Burma insisted again on Thursday it was capable of coping with the crisis.
The state media New Light of Myanmar newspaper said the people "will not rely too much on international assistance and will reconstruct the nation on a self-reliance basis".
The Red Cross has estimated the death toll at between 68,800 and 128,000.
The junta has also announced that 92.4% of voters had backed its proposed constitution in a national referendum held last weekend.
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