Earlier Gambari had flown from the remote administrative capital Naypyidaw where he had held two meetings with Foreign Minister Nyan Win, officials said.
They said the UN special envoy to Myanmar was not expected to meet detained democracy leader Aung San Suu Kyi before flying out of the country on a Thai Airways flight in the early evening.
Gambari arrived in the country for talks with the military regime on Friday and is due to brief UN chief Ban on the outcome of his mission.
Ban will then decide whether to go ahead with plans to visit Myanmar early next month, according to UN sources in New York.
The UN boss and Gambari have been trying to persuade Myanmar's ruling generals to free all political detainees, including Aung San Suu Kyi, and steer their country on the path to democracy and national reconciliation.
Aung San Suu Kyi, 64, is being held in jail on charges of violating her house arrest after American John Yettaw swam to her lakeside house earlier this year. She faces up to five years in prison if convicted.
She has spent 13 of the past 19 years in detention since the ruling generals refused to recognise the landslide victory of her National League for Democracy party (NLD) in 1990 elections.
Critics accuse the junta of trying to keep her locked up ahead of a poll promised in 2010.
Gambari was named the top UN envoy for Myanmar in 2006 but his previous visits have produced few results.
Aung San Suu Kyi refused to meet him in August 2008, apparently after he failed to secure reform pledges from the regime.
The charges against Aung San Suu Kyi come amid a wide-ranging crackdown on the opposition that has been carried out since the ruling generals crushed protests led by Buddhist monks in 2007.
More than 2,100 political prisoners remain imprisoned, according to United Nations figures.
Yettaw, a devout Mormon and US military veteran, has told the trial that he swam to Aung San Suu Kyi's home because he was on a mission from God to warn her about a "vision" that she would be assassinated.
The junta appeared to toughen its stance on the eve of Gambari's visit when the national police chief held a press conference to show alleged links between Yettaw and exiled dissident groups based in Thailand.
The case has drawn widespread international condemnation, with US President Barack Obama describing it as a "show trial" and some of Myanmar's neighbours breaking their usual silence on the issue.
The United States and Europe have both imposed sanctions against Myanmar, formerly known as Burma, which has been ruled by the military since 1962.
---------------------------------------------------------------------------------------------------------------------------
They said the UN special envoy to Myanmar was not expected to meet detained democracy leader Aung San Suu Kyi before flying out of the country on a Thai Airways flight in the early evening.
Gambari arrived in the country for talks with the military regime on Friday and is due to brief UN chief Ban on the outcome of his mission.
Ban will then decide whether to go ahead with plans to visit Myanmar early next month, according to UN sources in New York.
The UN boss and Gambari have been trying to persuade Myanmar's ruling generals to free all political detainees, including Aung San Suu Kyi, and steer their country on the path to democracy and national reconciliation.
Aung San Suu Kyi, 64, is being held in jail on charges of violating her house arrest after American John Yettaw swam to her lakeside house earlier this year. She faces up to five years in prison if convicted.
She has spent 13 of the past 19 years in detention since the ruling generals refused to recognise the landslide victory of her National League for Democracy party (NLD) in 1990 elections.
Critics accuse the junta of trying to keep her locked up ahead of a poll promised in 2010.
Gambari was named the top UN envoy for Myanmar in 2006 but his previous visits have produced few results.
Aung San Suu Kyi refused to meet him in August 2008, apparently after he failed to secure reform pledges from the regime.
The charges against Aung San Suu Kyi come amid a wide-ranging crackdown on the opposition that has been carried out since the ruling generals crushed protests led by Buddhist monks in 2007.
More than 2,100 political prisoners remain imprisoned, according to United Nations figures.
Yettaw, a devout Mormon and US military veteran, has told the trial that he swam to Aung San Suu Kyi's home because he was on a mission from God to warn her about a "vision" that she would be assassinated.
The junta appeared to toughen its stance on the eve of Gambari's visit when the national police chief held a press conference to show alleged links between Yettaw and exiled dissident groups based in Thailand.
The case has drawn widespread international condemnation, with US President Barack Obama describing it as a "show trial" and some of Myanmar's neighbours breaking their usual silence on the issue.
The United States and Europe have both imposed sanctions against Myanmar, formerly known as Burma, which has been ruled by the military since 1962.
---------------------------------------------------------------------------------------------------------------------------