North Korea is a regimented and repressive society, say refugees
North Korea still runs six prison camps holding 154,000 political prisoners, a South Korean lawmaker has said.
Yoon Sang-hyun, of the ruling Grand National Party, said inmates worked long hours in return for meagre food rations, reported Yonhap news agency.
Mr Yoon said he was basing his claims on a South Korean government report.
North Korea denies claims it abuses human rights. Earlier this year it amended its constitution to refer to its "respect" for human rights.
But human rights groups and North Korean refugees describe blatant, widespread and ongoing violations of basic rights in the Stalinist country.
In his statement to the National Assembly, Mr Yoon said North Korea used to operate 10 labour camps holding some 200,000 people in the 1990s, but had closed four under international pressure.
But he said six large camps were still going, holding dissidents, those who had attempted to flee the country, the losers in political power struggles, and ordinary North Koreans accused of being disrespectful towards the leadership.
'Crimes against humanity'
These 154,000 inmates - who are held in separate prisons from common criminals - are forced to work more than 10 hours a day on only 200g (7oz) of food, and are denied medical care, Mr Yoon said.
"North Korea perpetrates various crimes against humanity, including public executions, tortures or rapes, against those who try to escape," Mr Yoon was quoted as saying.
Observers say that over recent years South Korea has often been reluctant to highlight evidence of rights abuses in its northern neighbour for fear of jeopardising attempts at rapprochement.
But South Korea's conservative President Lee Myung-bak pledged to be more openly critical of the North's authoritarian regime when he took office last year.