* Navi Pillay says time right for international inquiry
* Torture, rapes, executions may be crimes against humanity
* Regrets nuclear issue has overshadowed concern on abuses
* North Korean envoy dismisses accusations
By Stephanie Nebehay
GENEVA, Jan 14 (Reuters) - U.N. human rights chief Navi Pillay called on Monday for an international investigation into what she said may be crimes against humanity in North Korea, including torture and executions of political prisoners held in shadowy camps.
She voiced regret that there had been no improvement since Kim Jong-un took power a year ago, succeeding his late father, and said it was time for world powers to help bring about change for the "beleaguered, subjugated population" after decades of abuse.
"Because of the enduring gravity of the situation, I believe an in-depth inquiry into one of the worst - but least understood and reported - human rights situations in the world is not only fully justified, but long overdue," Pillay said in a rare statement on North Korea.
The reclusive country's network of political prison camps are believed to contain 200,000 people or more and have been the scene of rampant violations including rapes, torture, executions and slave labour, according to Pillay, a former judge at the International Criminal Court.
These "may amount to crimes against humanity", she said.
Living conditions in the camps are reported to be "atrocious" with insufficient food, little or no medical care and inadequate clothing for inmates, she said.
"The death penalty seems to be often applied for minor offences and after wholly inadequate judicial processes, or sometimes without any judicial process at all," Pillay said.
"People who try to escape and are either caught or sent back face terrible reprisals including execution, torture and incarceration, often with their entire extended family."
Pillay regretted that international concerns over North Korea's nuclear programme and rocket launches were overshadowing "the deplorable human rights situation in the DPRK (Democratic People's Republic of Korea) which, in one way or another, affects almost the entire population and has no parallel anywhere else in the world".
Ri Jang Gon, deputy ambassador at North Korea's mission to the United Nations in Geneva, categorically dismissed the allegations. "We totally reject the news release. Our country doesn't have such kind of crimes," Ri told Reuters.
Instead, Pillay should examine the record of the "king of human rights abuses, the United States", he said.
North Korea has long argued that, hemmed in by a hostile United States and its allies, Japan and South Korea, it has no choice but to build up a powerful defence. Pyongyang is under U.N. sanctions for conducting nuclear tests in 2006 and 2009.
Kim, the third generation of a ruling dynasty, is the youthful new leader of the destitute country and he has overturned the austere image of his father, cheerfully riding a rollercoaster in an outdoor theme park.
"There were some initial hopes that the advent of a new leader might bring about some positive change in the human rights situation in DPRK," Pillay said. "But a year after Kim Jong-un became the country's new supreme leader, we see almost no sign of improvement."
Japan is weighing whether to submit a resolution on North Korea to the United Nations Human Rights Council, whose next four-week session begins on Feb. 25, diplomats said.
North Korea has ignored a series of council special investigators for years, denying them entry. But the 47-nation rights council has the power to launch wider independent international inquiries that can build a criminal case.
"We're hoping the session will be an opportunity to set up a commission of inquiry on North Korea. We believe the U.N. needs to strengthen its engagement," Julie de Rivero, director of the Geneva office of Human Rights Watch, told Reuters.
"It would be an evidence-gathering exercise. Fifteen years ago it probably was not possible but with so many North Koreans outside the country there's a lot of testimony to collect."
Former New Mexico state governor Bill Richardson and Google Executive Chairman Eric Schmidt failed to secure the release of a Korean-American held in North Korea during a trip to the secretive East Asian state last week.
The timing of their trip was criticised by the U.S. State Department, coming after Pyongyang carried out a long-range rocket launch last month, something Washington considers a provocative test of ballistic missile technology.
Pillay said that she had met two survivors of North Korea's labour camps in Geneva in December and their personal testimonies had been "extremely harrowing".
One of them, a man, had been born in a camp and spent 23 years there, subjected to torture and forced labour. At 14 he was made to watch his mother and brother being executed.
Pillay said there was an urgent need to clarify the fate of the many South Koreans and Japanese abducted by DPRK over the years as well as those taken to the North during the Korean War.
She urged "truth, justice and redress for their long-suffering families".