Burma's junta has refused to allow visiting UN Secretary General Ban Ki-moon to meet jailed opposition leader Aung San Suu Kyi.

Mr Ban was told of the refusal when he held a second round of talks with military leader Gen Than Shwe.

"I'm deeply disappointed," he told reporters. "I'm very sorry to report to you that this is not possible."

Ms Suu Kyi's trial on charges of breaking the terms of her house arrest was postponed again on Friday.

Mr Ban said Than Shwe had told him during their 30-minute meeting, in the remote administrative capital Nay Pyi Taw, that Ms Suu Kyi was on trial and he did not want to interfere with the judicial process.

The UN leader later left for Burma's main city, Rangoon.

Mr Ban's had a two-hour meeting with Gen Than Shwe on Friday.

Mr Ban said he had been assured that elections planned for 2010 would be "held in a fair, free and transparent manner".

The UN chief is due to make a speech outlining his vision for Burma later on Saturday.

Ms Suu Kyi, a Nobel Peace laureate, has spent much of the past two decades in prison or under house arrest.

She was transferred from house arrest to prison in May after an American man swam to her lakeside house.

She faces up to five years in jail if convicted.

Next year's elections are part of the military government's "roadmap to democracy," but critics say they will be a sham designed to strengthen the generals' four-decade grip on power.

Opposition activists say Ms Suu Kyi's trial is designed to keep her out of the way until after the elections.