Aid agencies are warning supplies are not getting to the areas worst hit
A UK minister, who is in Rangoon to press Burma's leaders to do more for Cyclone Nargis victims, says the aid operation "is now starting to move".
Lord Malloch-Brown says that although only about 25% of victims have received the help they need, he saw UK and US aid being unloaded at Rangoon airport.
His comments came just before a UN humanitarian envoy arrived in Burma for talks about widening the relief effort.
John Holmes will meet members of the junta and visit the Irrawaddy Delta.
The UN's emergency relief co-ordinator was met at the airport by Burma's Deputy Foreign Minister Kyaw Thu.
Mr Holmes is carrying a letter from UN Secretary General Ban Ki-moon to Burma's leader, Than Shwe, who has refused to answer Mr Ban's calls.
Burma says some 78,000 people have died and 56,000 are missing since Cyclone Nargis hit.
Save the Children says 30,000 acutely malnourished children are threatened by death from starvation.
Speaking to the BBC from Rangoon, Lord Malloch-Brown said that there had been "bottlenecks in the relief operation, many of them man-induced rather than natural," but that now aid was starting to be delivered.
He said that though the relief effort had not been what many Western nations considered sufficient, thanks to support from the governments of the region and the Association of South East Asian Nations (Asean) a compromise had been struck that the "Burmese can work with".
He said that aid workers are insisting that the needs of the cyclone victims are not being met, and the Burmese junta has a much more optimistic view of the situation on the ground.
Therefore, Lord Malloch-Brown says, the vital thing now is for a comprehensive assessment of exactly what is help is needed.
Running out of time
His visit comes as Save the Children UK's chief executive, Jasmine Whitbread, expressed concern that children in the worst-affected areas were suffering from "acute malnourishment" - the most serious level of hunger.
The charity said 30,000 under-fives in the Irrawaddy Delta were malnourished before Cyclone Nargis hit on 2 May and that that if they do not receive energy-rich food now they could starve to death within weeks.
The cyclone has filled rice fields with sea water, destroying vital crops
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