By Larry Jagan BBC Burma analyst

The United Nations Human Rights Rapporteur for Burma, Professor Paolo Sergio Pinheiro, is scheduled to begin another mission to the country on Thursday.

During his 11-day trip he will be meeting government ministers, ethnic leaders and members of the opposition, including the leader of the National League for Democracy, Aung San Suu Kyi.

Activists say Shan women have been victimised

Mr Pinheiro's primary concern this visit will certainly be to investigate the allegations that the Burmese army routinely rapes ethnic women along the border with Thailand.

Two organisations representing the Shan community said in a report earlier this year that Burmese troops had raped more than 600 Shan girls and women since 1996.

But UN officials say Mr Pinheiro will not be trying to assess the validity of the specific allegations on the report recently published by the two human rights groups based in Thailand.

Generals' denial

Instead, they say, he will be looking at the broader issue of the safety of women in conflict areas along the border.

While he will be visiting Shan state to see the situation there for himself, he is likely to be urging the Burmese generals to give his research team extended access to Shan state after he leaves.

The Burmese Government has already dismissed the claims as a tissue of lies created by organisations whose sole desire is to discredit the regime.

But the generals will be disappointed if the UN envoy is going there to back their position.

Political prisoners

Mr Pinheiro is also concerned about the conditions of Burma's prisons and the issue of political prisoners.

The military government has freed more than 300 since they started secret talks with the opposition leader, Aung San Suu Kyi, two years ago.

But more than 1,000 are still in jail, according to international human rights groups.

The UN envoy Razali Ismail who brokered the talks between the two sides, has been urging the generals to free the remaining political prisoners as soon as possible.

Mr Pinheiro has also consistently urged the regime to release all the country's political prisoners immediately.

He is likely to be reinforcing that message again on this trip.

Progress on this issue is needed if the dialogue process between the opposition leader, Aung San Suu Kyi, and the generals is to make any further progress.