By Charles Haviland
BBC News, Kathmandu
The United Nations official in charge of investigating instances of torture around the world has arrived in Nepal for a week-long visit.
Mr Nowak's visit comes during a rebel ceasefire
The visit by Manfred Nowak comes as concern grows at the increasing incidence of the practice in the violence-stricken kingdom.
Torture happened in Nepal before the start of the Maoist insurgency in 1996.
But with the onset of that conflict, human rights groups say the number of victims has risen.
They say both the government and rebel sides use torture on a widespread basis.
They also say that while each side sometimes takes action against its own people who have killed, torturers are never punished in the same way.
A leading Nepali organisation, Centre for the Victims of Torture or C-Vict, says nearly 5,000 cases of physical or psychological torture were reported to it last year.
But it adds that victims are now getting more afraid of coming forward.
It also says it is having problems funding professional treatment and sending its experts into conflict-hit areas.
Nepal has the world's highest rate of fresh political disappearances, and C-Vict says that people who disappear have often been tortured to death.
During his seven-day visit, the UN official is to visit places where the government side detains people.
Manfred Nowak will later submit a written report on Nepal to the next session of the UN Commission on Human Rights.
His visit comes a week into a three-month ceasefire called unilaterally by the Maoists.
Each side has already accused the other of behaving violently, but the size and frequency of such incidents do appear to be down.