"Japan's sexual slavery was an unprecedented, the gravest and the most vicious violation of human rights in history," Hong Sun-Ok, North Korea's chief delegate, said.
About 100 people from 10 countries heard women from South Korea, the Philippines and Taiwan talk about being Japan's sex slaves.
Wu Hsiu Mei, 90, said she was put in a Japanese army brothel in Guangzhou, China, and gang raped.
"At the station ... there were 30 Japanese forces. They were scary. I was raped by the troops, all of the soldiers there," she added.
Rape and torture
|Pilar, left, said she serviced up to six Japanese|
soldiers a night
Pilar Frias, 80, of the Philippines, testified at the forum that she had to service up to six Japanese soldiers every night while travelling with troops for two months.
"I am the right evidence that there was coercion," she said, pointing to her facial burn scar she said was sustained while resisting being taken by the Japanese.
"I'm very, very ugly now because the Japanese soldier is the one who make this ugliness."
Pilar said she was kept tied by a rope to other women who served the soldiers by day and were raped at night.
"I can never forgive them for all I suffered in their hands… every time I look in the mirror and see this… that's my first memory of hardship by their hand," she added.
In the 1990s, 174 Filipino women came forward claiming to have served as sex slaves for Japan's soldiers. Many of them have since died.
|Lita, right, entering the 'Red House' where 80 or|
so women and girls were raped
But there are some who have been told they did not even qualify for compensation because they were not kept as "comfort women".
Lita Vinuya and her childhood friend Pilar Galang were among 80 women and girls – some as young as 11 – from Mapanique, a village 150km north of Manila, who were systematically raped in the Red House, the local Japanese army headquarters during the war.
Lita said she still remembers the room where Japanese soldiers raped five girls, including her, in the Red House.
The women have also written songs to remind the world of the "blackest night" of their lives.
|Lita, right, and Galang say that night was the|
"blackest night" of their lives
Despite receiving "atonement" money from mostly private groups, the Filipino sex slaves want justice directly from the Japanese government, as well as for their stories to be noted as fact in history books.
Shinzo Abe, the Japanese prime minister, provoked a furore in Asian nations in March when he denied that comfort women were forced into sexual slavery "in the strict sense of coercion".
Abe has said he stands by Japan's landmark 1993 apology to the women and last month stressed his sympathy for Asian women driven into brothels by Japan's military.
Historians say up to 200,000 young women, mostly from Korea but also from China, Indonesia, the Philippines and Taiwan, were forced to serve as sex slaves in Japanese army brothels.