IMAGINE being forced to kill your own baby.

That sort of horror is a daily occurrence in North Korea's prison camps, former inmates have told a United Nations inquiry.

The inquiry, chaired by former Australian High Court Justice Michael Kirby, is the first to expertly examine North Korea's human rights record, ABC News reports.

There is no shortage of testimony.

One ex-prisoner, 34-year-old Jee Heon-a, told the hearing about a mother who was forced to drown her own child.

"It was the first time I had seen a newborn baby and I felt happy," she said.

"But suddenly there were footsteps and a security guard came in and told the mother to turn the baby upside down into a bowl of water.

"The mother begged the guard to spare her, but he kept beating her. So the mother, her hands shaking, put the baby face down in the water. The crying stopped and a bubble rose up as it died."

Jee was incarcerated in 1999. Her fellow inmates were barely fed.

"Everyone's eyes were sunken. They all looked like animals, she said.

"Frogs were hung from the buttons of their cloths, put in a plastic bag and their skins peeled off. They ate salted frogs and so did I."

Another defector, Shin Dong-hyuk, was forced to watch the execution of his mother and brother. Shin, who was born in the prison camp, overheard his family members planning an escape attempt and turned them in.

In a separate incident, the North Korean guards chopped off Shin's finger after he accidentally dropped a sewing machine.

"I thought my whole hand was going to be cut off at the wrist, so I felt thankful and grateful that only my finger was cut off," Shin said.

There are 150,000-200,000 people trapped in North Korean prison camps, Reuters reports.

The UN hearing was held in South Korea's capital city, Seoul. Only a few dozen people attended.