The United Nations on Tuesday named a team of three human rights investigators who will look into allegations of torture and labor camps in North Korea that are believed to hold at least 200,000 people.

Pyongyang denies the existence of such camps and is not expected to cooperate with the investigation, having denounced it during a UN Human Rights Council debate, activists said.

But the one-year inquiry, launched by the council on March 21, hopes to gather enough information from camp survivors and other exiles to document violations that it says may amount to crimes against humanity and build a case for future prosecution.

"There is sufficient evidence outside of North Korea about what is happening inside, so the government can't keep a lid on it any more. That's why this investigation is so needed," said Julie de Rivero of Human Rights Watch.

Michael Donald Kirby, a former justice of Australia's High Court, and Sonja Biserko, a founder of the Helsinki Committee for Human Rights in Serbia, are to join Indonesia's Marzuki Darusman, its current special rapporteur on North Korea, on the team, to be backed by researchers, lawyers and forensic experts.

"Mr. Kirby will serve as chair of the three-person commission," said a statement issued by the president of the Geneva forum, Poland's ambassador Remigiusz Henczel, who held wide consultations with diplomats before naming the team.

The council unanimously passed a resolution brought by the Europe Union and Japan, and backed by the US, which set up the inquiry and condemned alleged North Korean torture, food deprivation and labor camps.

Activists hope the investigation, which is due to produce a preliminary report in September, will help expose decades of abuse by North Korean government.

UN human rights chief Navi Pillay called in January for the "long-overdue" investigation, saying that she regretted there had been no improvement since Kim Jong-un took power a year earlier.

Reuters