Veteran Australian high court judge Michael Kirby says he was reduced to tears by witness accounts of people who fled North Korea.
Kirby, the head of a UN inquiry into North Korean rights abuses says the treatment of women returned to North Korea after already being abused in China was particularly tough.
The UN Human Rights Council commission of inquiry has heard evidence in London, Tokyo and Seoul and will be in Washington from Wednesday.
The inquiry has heard harrowing stories of labour camps in the isolated state ruled by Kim Jong-Un as well from relatives of Japanese believed abducted by North Korean agents and families divided since the 1950-53 Korean War.
"Some of the testimony has been extremely distressing," Kirby, who has also investigated abuses in Cambodia, told a press conference after addressing a UN General Assembly committee.
"I am a judge of 35 years experience and I have seen in that time a lot of melancholy court cases which somewhat harden one's heart.
"But even in my own case, there have been a number of the testimonies which have moved me to tears and I am not ashamed to say that.
"You would have be a stony-hearted person not to be moved by the stories that the commission of inquiry has received," he declared.
Kirby said the testimonies "should be seen and they should be considered for the follow up that will be required" by the UN system. All of the testimonies have been put online.
He said women "figure very greatly in testimony" and make up the majority of the North Koreans who have tried to flee the tightly controlled state.
"Many of them have left and gone on to China where they are subject to forced marriages, trafficking and other human rights burdens," he added.
But China sends back many who are caught and those women "have suffered very grievously," Kirby said.
North Korea has condemned the UN inquiry as "hostile" and said the witnesses are liars.
The final report will be presented to the Human Rights Council in March.
