An unprecedented study into human rights abuses in North Korea has detailed the government's alleged crimes against humanity.

The UN inquiry's report said that police and security forces "systematically employ violence and punishments that amount to gross human rights violations".

It added that torture is an "established feature of the interrogation process", and that food is used as a means of control over the population.

Inquiry chairman Michael Kirby said the crimes were "strikingly similar" to Nazi-era atrocities.

He said the number of officials likely to be responsible for the gravest crimes potentially runs "into hundreds", and that the findings of his report are "gruesome".

However the secretive regime said the report was based on material faked by hostile forces backed by the United States, the European Union and Japan.

In a letter to North Korean leader Kim Jong-Un, the commissioners said they would recommend the situation be referred to the International Criminal Court.

They said the court could "render accountable all those, including possibly yourself, who may be responsible for the crimes against humanity referred to in this letter and in the commission's report."

The report strongly criticised North Korea's denial of basic freedoms of thought, expression and religion, and its abduction of citizens of neighbouring South Korea and Japan.

It 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."

The United States said the report "clearly and unequivocally documents the brutal reality" of North Korea's human rights abuses".

State Department deputy spokeswoman Marie Harf said it reflected "the international community's consensus view that the human rights situation in the Democratic People's Republic of Korea is among the world's worst".