Mr Ban visited the "show" relief camp in the Irrawaddy Delta
UN Secretary General Ban Ki-moon has held talks in Burma's remote capital with top leader Gen Than Shwe, a day after touring cyclone-hit areas.
On Thursday, Mr Ban flew over flooded rice fields and destroyed villages and visited a government relief camp.
Burma's military leaders, who have been accused of not doing enough to alleviate the situation, say they have everything under control.
About 78,000 people died and 56,000 are missing after the 2 May cyclone.
Correspondents say signs for the talks are encouraging - Gen Than had previously failed to answer Mr Ban's phone calls and letters.
Relief phase 'over'
The UN hopes he Gen Than Shwe will now be more receptive to its main requests - to allow more foreign disaster experts into the delta, to allow international aid agencies to put a forward logistics base there and allow foreign planes, boats and helicopters in.
But earlier in the day, Burma's Prime Minister Thein Sein told Mr Ban that the relief phase of the aid operation was over and that the government was now focusing on reconstruction, a UN official said.
The secretary general's visit has won backing from the United States.
"We are certainly supportive of what Ban Ki-moon is doing," Secretary of State Condoleezza Rice told the BBC.
"We are working through the Chinese, through the Asean countries, we are using every means to try to get in."
UK Foreign Secretary David Milliband told the BBC: "The tragedy is that, for some people it is already too late, and it is certainly too little compared to the needs, but we have got to use the opportunity that exists."
"We've got to keep pushing that door open and working to ensure that those desperate people get the help that they need," he added.
Mr Ban arrived in Burma on Thursday and visited a relief camp in the Irrawaddy Delta.
A UN official privately called it a "show camp", says the BBC's Laura Trevelyan, in Burma with the secretary general.
Mr Ban told a woman: "I am so sorry, but don't lose your hope."
"The United Nations is here to help you. The whole world is trying to save Myanmar [Burma]."
Mr Ban told reporters he was "very upset" by the devastation he had seen.
"Many human lives have been lost, houses are destroyed, roads and streets are washed away, and all rice paddies flooded with water. I'm very much concerned. These farmers may lose their planting season," he said.
Mr Ban told the prime minister that the disaster was beyond Burma's ability to handle on its own and that foreign aid experts should be rushed in.
"The United Nations and all the international community stand ready to help to overcome the tragedy," Mr Ban is quoted as saying.
Ban Ki-Moon on the need for Burma to allow more aid in
He said relief work would have to continue for many more months.
The UN estimates that only a quarter of the 2.5m Burmese affected by the cyclone have received the help they need.
The Red Cross has said that in districts further south-west of those shown to Mr Ban, waterways were still clogged with corpses and that many people had received no aid.
One foreign doctor told the BBC many were drinking water from puddles, while children and old people were suffering from dysentery, dengue fever and dehydration.
The generals have agreed that some UN helicopters can join the aid effort, but British, French and American naval vessels are still standing by off the Irrawaddy Delta, having been refused access to the area.
The first of 10 helicopters to be sent by the UN's World Food Programme arrived in Burma on Thursday, and will be used to ferry supplies to remote areas.
The government has also agreed to allow in more foreign aid workers from its Asian neighbours.
Mr Ban is due to attend a donor conference in Burma's commercial capital, Rangoon, on Sunday.
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