UK Prime Minister Gordon Brown says new sanctions may be imposed on Burma's regime after it snubbed visiting UN Secretary General Ban Ki-moon, BBC reported.
Mr Ban expressed "deep disappointment" after Burma's top general rejected his request to meet with detained opposition leader Aung San Suu Kyi.
In London, Mr Brown attacked the "obstinacy" of the regime and raised "the possibility of further sanctions".
He reacted after Mr Ban's two-day visit to Burma ended with little progress.
"We await the secretary general's report. I hope that there is still the possibility of a change of approach from Burma but if not, my sad conclusion is that the Burmese regime has put increased isolation - including the possibility of further sanctions - on the international agenda," Mr Brown said.
"It is a measure of the obstinacy of the Burmese regime that they have once again failed to respect [the UN's] principles, and failed to properly respond to the international figurehead who best embodies them."
Mr Ban said he was told by Gen Than Shwe that he could not see Ms Suu Kyi because she was on trial.
Ms Suu Kyi is charged with breaking the terms of her house arrest. Her trial was postponed again on Friday.
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.
Ms Suu Kyi, a Nobel Peace laureate, has spent much of the past two decades in detention.
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.