North Korea's regime is committing crimes against humanity including the extermination, starvation and enslavement of its population, and its leadership should be hauled before an international court, a UN-mandated inquiry team has said.

The UN Commission of Inquiry on Human Rights in North Korea published its report on Monday, with evidence of torture, rape and murder inside the country's labour camps where political prisoners are held.

Presenting the report, the commission's chairman Michael Kirby charged that the leaders of the state, including the supreme leader, Kim Jong-un, should answer evidence that they preside over such crimes against their people.

Kirby said: "The commission of inquiry came to the conclusion that there is abudant evidence ... those who are in positions of power are accountable. All lines of authority stop at the supreme leader."

However, he said that the commission was not a tribunal nor a prosecutor, and it was for an international court to decide on any prosecution.

"We have not judged the supreme leader. Our job is to assemble the material and express conclusions."

Kirby said: "In the course of this inquiry we have been asked, 'can you expect anything to be done?' I do. This report will galvanise action from the international community.

"How can we [ensure] those accountable to their own people, to their victims and to the bar of history? We expect and hope that the international community will respond."

"At the end of the second world war, so many people said: If only we had known... Now the international community does know. There will be no excusing of failure of action because we didn't know."

Powerful evidence

The UN commission was set up last March to begin building a case for possible criminal prosecution. It called more than 80 public hearings, and also used evidence gathered by the human rights group, Amnesty International.

Its report, which will be presented to the UN Human Rights Council next month, said: "Systemic, widespread and gross human rights violations have been and are being committed by the Democratic People's Republic of Korea, its institutions and officials.

It detailed "extermination, murder, enslavement, torture, imprisonment, rape, forced abortions and other sexual violence".

"In many instances, the violations of human rights found by the commission constitute crimes against humanity. These are not mere excesses of the State; they are essential components of a political system."

Al Jazeera's diplomatic editor James Bays said the UNHCR can only refer the evidence to the Security Council before any charges can be laid in the International Criminal Court.

China, North Korea's only international ally, is a permanent member, and has the power of veto.

North Korea earlier on Monday hit out at the UN in a statement sent to Reuters. The government called the UN report "fabricated and invented" and an "instrument of political plot".

"However, we will continue to strongly respond to the end to any attempt of regime-change and pressure under the pretext of 'human rights protection'," it said.

"The DPRK once again makes it clear that the human rights violations mentioned in the so-called 'report' do not exist in our country."