Over 10,000 people die in North Korean prison camps every year, 20 to 25 percent of them from forced labor, the International Coalition to Stop Crimes Against Humanity in North Korea said Tuesday.

The group consists of some 40 leading human rights organizations and activists including the world's big three -- Amnesty International, Human Rights Watch and the International League for Human Rights -- and was established in September last year.

In a press conference Tuesday it called on the UN to carry out a special investigation of North Korean gulags and said it submitted a petition to the UN Human Rights Council.

Based on testimonies of North Korean defectors, it says there are six political prisons in the Stalinist country housing 150,000 to 200,000 people who are subject to inhumane treatment such as forced labor, torture and public execution. It said the work of just one UN special rapporteur on North Korea is not enough to save the vast number of political prisoners there and urged the UN to establish a commission to investigate crimes against humanity in the isolated country.