Campaigners urged China to give citizenship to a 'hidden generation' of stateless children born to trafficked North Korean women forced into marriage or prostitution in China.
They said an estimated 20,000 to 30,000 children born to North Korean women in China have no nationality and therefore cannot access education, healthcare and basic rights that most people take for granted.
If their mothers are deported, they are often abandoned by their Chinese fathers, leaving them effectively orphaned, according to the European Alliance for Human Rights in North Korea (EAHRNK).
Thousands of North Koreans have fled hunger and oppression in the secretive state since a famine in the mid-1990s. Many are in hiding in neighbouring China, which considers them illegal migrants.
The plight of their children is outlined in an EAHRNK report co-authored by Yong Joon Park, a teenager now living in Britain who grew up stateless in China.
His mother, Jihyun Park, told the Thomson Reuters Foundation traffickers sold her as a wife to a poor Chinese farmer after she fled North Korea in 1998.
In 2004, when their son was five, she was reported to the authorities and deported back to North Korea.
There she was sent to a labour camp where she endured "horrific conditions" and prisoners were "worked harder than animals".
"All I could think of was seeing my son again," said Park, who eventually managed to escape and return to China.
She found her son but barely recognised him. His skin was filthy and flaking, and when he was hungry he was sent outside to pick up grains of rice from the ground.
"They treated him badly. His life was worse than the starving children in North Korea," she said. "The Chinese government does not give children like my son a nationality so they cannot go to school."
She and her son managed to cross the Chinese border into Mongolia and later moved to Britain as refugees.
"When my son arrived in the UK he was nine. It was the first time he had a nationality and the first time he went to school."
Now 16, he scored straight As in his exams this year and is hoping to go to university to become a lawyer.
EAHRNK director Michael Glendinning said the Chinese authorities were making no effort to find a solution for such children. "The Chinese government have just washed their hands and are refusing to do anything about it," he said.
"They won't give these children the status they need to access the most basic of things. Legally, they don't even have a name."
The report also urged China to stop repatriating North Koreans.
The Chinese embassy in London could not immediately comment.
The U.N. refugee agency (UNHCR) launched a global campaign last year to eradicate statelessness within a decade. The children in China are among an estimated 10 million stateless people worldwide.
U.N. human rights investigators have accused North Korea of abuses comparable to Nazi-era atrocities and say that defectors sent back face torture, imprisonment and even execution.
