Aid agencies are frustrated they cannot get aid to those that need it most
France's ambassador to the UN has accused Burma's government of being on the verge of committing a crime against humanity by not accepting foreign aid.
Jean-Maurice Ripert made the comment during a General Assembly session, after Burma's UN ambassador accused France of sending a warship to region.
France says the ship is carrying 1,500 tonnes of food and medicine for survivors of Cyclone Nargis.
State TV has put the official death toll of the 2 May storm at 78,000.
Another 56,000 people are thought to be missing according to the latest official estimates, which nearly double the figures released on Thursday, raising fears the final human toll may be enormous.
UK Prime Minister Gordon Brown has said a natural disaster has been turned into a man-made catastrophe because of the negligence of the Burmese generals.
"The responsibility lies with the Burmese regime, and they must be held accountable," Mr Brown told the BBC.
Refusing aid by sea
Mr Ripert angrily rejected Burmese allegations the French ship in international waters off Burma's coast was a warship.
People wait for help in the worst-hit Irrawaddy Delta
The French UN ambassador warned that the Burmese government's refusal to allow aid to be delivered to those who needed it "could lead to a true crime against humanity".
"Hundreds of thousands of lives are in jeopardy and we think that the primary responsibility of the government of Myanmar (Burma) is to help and open the borders so that the international aid could come into the place," he said.
A US naval task force is also waiting off the Burmese coast for permission to deliver large consignments of aid, including drinking water, but so far the Burmese military government has refused relief aid arriving by sea.
Foreign aid agencies, too, are frustrated at the slow progress of aid to areas worst hit, especially in the Irrawaddy Delta.
However, a team of 50 Indian medical personnel is being flown into Rangoon on Saturday, equipped with medical supplies.
The BBC's Sanjoy Majumder says the government is making an exception to its reluctance to accept foreign aid, because India has close ties to the Burmese junta.
A BBC reporter in the delta this week saw little sign of official help and foreign aid workers have been barred from the area.
Natalia Antelava saw muddy river banks lined with white, swollen bodies, and found survivors with barely enough rice to live on.
The Red Cross is seeking more than $50m (£26m) in aid to help survivors of the storm which struck on 2-3 May.
Heavy rain has been lashing the region, compounding the misery of cyclone survivors.
The UN Humanitarian Co-ordinator, John Holmes, is due to visit Rangoon, Burma's main city, on Sunday in a bid to persuade the military government to grant more access to UN relief workers and expand its aid effort.
Earlier, the EU's top aid official, Louis Michel, was denied permission to visit the delta region. He said he was given no explanation why disaster emergency experts were being refused visas.
But Burma's authorities have promised to take foreign diplomats on a tour of the region this weekend, although it is not clear how much access the group will have to areas outside the official tour route.
'Beggars for miles'
Burma blamed its sudden increase in the estimated death toll on difficulties in confirming the extent of damage in the worst-affected areas.
Every possible pressure must be used to get them to understand that they must help us help them
The difficulty in getting accurate figures is inevitable bearing in mind the scarce resources there are on the ground to assess the needs of survivors, says the BBC's Chris Hogg in Bangkok.
A Reuters team travelling to Kunyangon, around 100km (60 miles) south-west of Rangoon, found rows of beggars stretching for miles on either side of a road.
Men, women and children stood in the mud and rain, hands clasped together in supplication at the occasional passing aid vehicle.
Many relief workers are awaiting visas and most of those who have been allowed into the country remain confined to Rangoon.
'Time is life'
Speaking in Bangkok after his visit to Burma, the EU's Louis Michel said the world needed to impress upon Burma's rulers the urgency of survivors' needs.
Further hardship awaits survivors whose crops have been destroyed
"Time is life," he said.
"Every possible pressure - all rhetorical and diplomatic means - must be used to get them to understand that they must help us help them."
At this stage it is not clear who he will be able to talk to given that Burma's leader, Thein Sein, has refused to answer calls from UN Secretary General Ban Ki-Moon.
In the last few days, Burma has agreed to allow a few experts from neighbouring countries in to help.
While this may not be as many as the international community thinks are needed, UN officials believe this is an opportunity to show the military government that aid-workers' motives are humanitarian, not political.
According to the Red Cross, aid agencies have been able to reach less than a third of cyclone victims and hundreds of thousands of people are at risk of diseases such as dysentery because of lack of clean water.
The Association of South East Asian Nations (Asean) is due to hold a high-level meeting in the coming days that is expected to lay the framework for a broader aid donors' conference.
Burma's military leadership, meanwhile, has warned that those who hoard or sell aid on the black market will be prosecuted, amid international reports of misuse of some aid shipments.
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