The highest ranking foreigner allowed to tour the disaster zone so far said he was "very upset by what I've seen", but offered cyclone victims a "message of hope".
"The whole world is trying to help Myanmar people. It will be very difficult for you, but please have strong courage and do not lose your hope, and please take good care of your children," he said.
"The United Nations and the whole international community stand
ready to help you overcome this tragedy."
But Than Shwe and his inner circle who have defied world opinion for decades and turned the once-prosperous country into one of the poorest have insisted they will handle the situation alone.
While welcoming thousands of tonnes of donated relief supplies, the government has blocked visas for most foreign disaster management experts and insisted reports of survivors not getting enough aid are the work of "traitors".
Instead it says the rescue operation is proceeding without trouble despite outbreaks of disease, dire shortages of basic supplies and international warnings of a possible famine.
It was not immediately clear how much headway Ban would make.
"The regime are not serious when they talk to Ban Ki-moon because they don't consider him a relevant actor," said Win Min, a Myanmar refugee and political analyst in neighbouring Thailand.
"They are trying to reduce the pressure, which is strong on them at the moment," he said.
The government did allow the first of 10 UN helicopters into the country on Thursday.
But the generals are still refusing to allow French, British and American warships waiting offshore to deliver humanitarian supplies.
France's UN ambassador says his country will push for a resolution to force aid on Myanmar by whatever means necessary if it does not open up voluntarily after meetings on Sunday with officials from the UN and the Association South-East Asian Nations.
On Thursday Ban visited a well-organised makeshift relief camp where 500 people huddled in blue tents in Dedaye township, about 75km southwest of Yangon, Myanmar's largest city.
But officials gave no explanation of why he was not taken to outlying areas further southwest in the townships of Labutta and Bogalay, where the majority of Myanmar's 134,000 dead and missing have been reported.
According to the Red Cross, rivers and ponds in Bogalay remain full of corpses and many people in remote areas have received no aid.
Myanmar's military government says some 78,000 people were killed in the May 2-3 cyclone and another 56,000 are still unaccounted for.
The UN estimates up to 2.5 million cyclone survivors – only 25 per cent of whom have received aid – are facing hunger and illness from unsanitary conditions, with children being the most vulnerable.
Ban said Myanmar's rulers had shown "some flexibility" over calls to ramp up relief efforts and wanted some $11bn worth of aid funding.
On Sunday, representatives of the UN and the Association of South-East Asian Nations are to meet in Yangon for an aid donors' conference.
Donors, however, are asking to see the devastated areas before they hand over the cash.
Following Ban's visit, foreign aid agencies stressed the need to quickly reach survivors suffering from disease, hunger and lack of shelter.
"In 30-plus years of humanitarian emergency work this is by far – by far – the largest case of emergency need we've ever seen," said Lionel Rosenblatt, president of US-based Refugees International.
Eain Daw Bar Tha, abbot of a Buddhist monastery on Yangon's outskirts, called for less talk and more action.
"The UN must directly help the people with helicopters to bring food, clothes and clean water to the really damaged places."
Source: Al Jazeera and agencies