National League for Democracy (NLD) spokesman Nyan Win told the BBC he had not been allowed to speak to detained opposition leader Aung San Suu Kyi.
Mr Win said he knew nothing of any further contact between Ms Suu Kyi and the military government.
The UN has repeatedly called for talks between the government and Ms Suu Kyi.
UN envoy Ibrahim Gambari has made two visits to Burma since tens of thousands of people joined massive street demonstrations led by monks, in Rangoon and other cities, in an outpouring of anger at the military government.
After his second visit early in November he read out a statement from Ms Suu Kyi in which she offered to take part in a dialogue with the military.
Ms Suu Kyi is under house arrest and this was the first time her words had been made public in years.
"I am committed to pursue the path of dialogue constructively, and invite the government and all relevant parties to join me in this spirit," she said.
While she insisted she would only take part in a serious and time-limited process, Mr Gambari presented this as an opening for talks to begin.
The generals had offered talks, but under conditions which the NLD felt were unacceptable, including renouncing support for sanctions against the Burmese government.
The fact that Ms Suu Kyi felt able to engage in talks suggested to some optimists that perhaps these terms had been relaxed.
But it seems these hopes have been dashed.
Only one meeting took place between Ms Suu Kyi and the government minister appointed negotiate with her, Aung Kyi. That was a month ago.
Mr Win told the BBC's Burmese service that he had not been allowed to speak to Ms Suu Kyi since before that meeting.
Meanwhile, the outside world continues to try to put moral pressure on the Burmese government.
On Monday the American House of Representatives voted unanimously to award Ms Suu Kyi a Congressional Gold Medal.
The award must yet be confirmed by the Senate.
The same award was given to the Dalai Lama earlier this year, much to China's fury.
However, this sort of symbolic action has had little effect on China's policies in Tibet.
Sceptics will say it is hardly likely to have a greater influence on the military government in Burma.