United Nations special envoy Ibrahim Gambari arrived in military-ruled Burma to explore the possibility of a visit next month by UN secretary general Ban Ki-moon.
Mr Gambari, making his eighth visit to the former Burma, left Yangon by car to travel 385km to the country's new capital Naypyidaw, a diplomat said.
The Nigerian was expected to meet foreign minister Nyan Win. It was not known if Gambari would see opposition leader Aung San Suu Kyi, who is on trial in Yangon for breaching terms of her house arrest by allowing an American intruder to stay at her home last month.
"Gambari will meet with the foreign minister later this afternoon about the possibility of the visit of Ban Ki-moon," the diplomat told reporters.
"He's spending tonight in Naypyidaw but we don't know his further plans yet. We're not sure whether he will get a chance to see Daw Aung San Suu Kyi."
Ms Suu Kyi's trial, which sparked anger around the world, was adjourned on Friday until July 3rd, when the court will hear the testimony of legal expert Khin Moe Moe, her lawyer Nyan Win said.
A higher court is yet to rule on an appeal against bans on two of Suu Kyi's other defence witnesses, senior National League for Democracy (NLD) member Win Tin and the party's detained vice-chairman, Tin Oo.
Critics have dismissed the case as a "show trial" aimed at keeping Suu Kyi out of planned multi-party elections next year.
She faces three to five years in prison if found guilty of violating a security law protecting the state from "subversive elements".
Mr Nyan Win said Ms Suu Kyi was in good health but knew nothing of Mr Gambari's trip.
"She had not known about the visit of Gambari until we told her," he told reporters.
Western diplomats at the United Nations said last week the junta had invited Mr Ban, who has expressed a desire to meet the generals to press for democratic reform and the release of Ms Suu Kyi and other political prisoners.
However, the diplomats, speaking on the condition of anonymity, said Mr Ban was concerned the regime would use the visit for propaganda purposes to try to legitimise Ms Suu Kyi's trial.
Reuters