UN envoy in Burma for talks
His latest visit is Mr Gambari's eighth trip to Burma
UN envoy Ibrahim Gambari is in Burma ahead of a possible visit by UN Secretary General Ban Ki-moon.
Mr Gambari was expected to meet Burmese Foreign Minister Nyan Win but it was not clear if he would meet jailed pro-democracy leader Aung San Suu Kyi.
She is on trial accused of breaking the terms of her house arrest by letting an uninvited US man stay in her home.
Mr Ban has said he hopes to press Burma's military rulers to release her and other political prisoners.
After arriving in Rangoon on Friday, Mr Gambari travelled to Burma's capital, Naypyidaw, where he was expected to hold talks with Foreign Minister Nyan Win.
After his two-day trip, Mr Gambari will brief Mr Ban before the UN chief decides whether to visit Burma in early July.
It is the special envoy's eighth visit to Burma to try to promote political reconciliation between the military government and the pro-democracy movement led by Ms Suu Kyi.
Before Mr Gambari arrived in Burma, the country's police chief said Ms Suu Kyi's visitor, John Yettaw, had links to Burmese exile groups in Thailand.
Mr Yettaw is also on trial over his visit to Ms Suu Kyi's lakeside home in Rangoon.
Ms Suu Kyi has been allowed few visitors since being detained
Her trial over the incident was again postponed on Friday until 3 July - the latest in a series of delays over allowing more defence witnesses.
Observers say the charges against Ms Suu Kyi - which carry a maximum punishment of five years in jail - are designed to keep her imprisoned until after next year's election.
She has already spent 13 of the past 19 years under house arrest, banned from seeing all but a small group of people.
Mr Ban is considering whether to visit Burma in early July but is wary of being used by Burma's generals to endorse their treatment of Ms Suu Kyi, says BBC UN correspondent Laura Trevelyan.
Human Rights Watch says the trial delay could make a visit by Mr Ban even more fraught.
"The latest postponement of the trial means the danger that the generals will manipulate Ban Ki-moon's visit are dangerously high," Steve Crawshaw from HRW told the BBC.
"Even if Aung San Suu Kyi is released from jail back into house arrest, that wouldn't be a genuine concession - she should never have been put under house arrest in the first place."
Burma's military rulers have refused to recognise the results of general elections in 1990, won by Ms Suu Kyi's National League for Democracy party.