GENEVA: North Korea's leaders are likely to be the target of a U.N. investigation into their personal responsibility for rapes, torture, executions, arbitrary arrests and abductions, following an expert report published on Tuesday.

The report by Marzuki Darusman, an Indonesian lawyer who is the U.N. Special Rapporteur on human rights in North Korea, said North Korea's "grave, systematic and widespread" human rights violations ought to be laid bare before the U.N. Human Rights Council and the U.N. General Assembly.

"The inquiry should examine the issues of institutional and personal accountability for such violations, in particular where they amount to crimes against humanity, and make appropriate recommendations to the authorities of the Democratic People's Republic of Korea (DPRK) and international community for further action," said Darusman's report.

Any such recommendations will not be binding and are unlikely to be heeded by North Korean leader Kim Jong-un, the third generation of a dynasty that has ruled the secretive authoritarian state throughout its history.

In theory, they could give sufficient legal grounds for the U.N. Security Council to refer North Korea to the International Criminal Court.

Such a move would be likely to be vetoed by China, but - as with the U.N. investigation into human rights in Syria - the amassing of information, based on accounts from defectors and refugees, could create a dossier that is harder to dismiss than individual allegations of abuses.

In a letter dated Jan. 28 and seen by Reuters on Tuesday, North Korea rejected Darusman and his mandate to scrutinise Pyongyang's human rights record, calling his role "a product of political confrontation and plot against the DPRK".

"The 'special rapporteur'... is none other than a marionette running here and there in order to represent the ill-minded purposes of the string-pullers such as the United States, Japan and the member states of the EU," said the letter, signed by North Korea's Ambassador So Se Pyong.

For decades, North Korea has refused to answer accusations about alleged crimes against humanity or allow any examination of a prison camp system suspected of holding 200,000 political prisoners.

A comprehensive and U.N.-backed cataloguing of the accusations may put pressure on China, which resisted a U.S. attempt to bring new U.N. sanctions over North Korea's ballistic missile launch in December, although it agreed to tighten the existing sanctions regime.

Pyongyang has threatened war with South Korea if it adopts the tighter sanctions and - according to South Korean and other observers - it is about to carry out a third nuclear test in defiance of U.N. censure.

U.N. Human Rights chief Navi Pillay called for an international investigation of the north last month. U.S.-based Human Rights Watch said there was growing support for resolutions at the Human Rights Council, noting that traditional defenders of North Korea - China, Russia and Cuba - were not members of the body in 2013.

"For the first time in the history of the U.N. there is certainty that a U.N. resolution establishing a Commission of Inquiry on North Korea would pass," Human Rights Watch said.