In order to make it easier to find victims and reunite them with their family, police also set up a database that collects DNA samples of victims and their parents. So far, the database has helped 813 children find their biological parents through DNA matching, the Ministry said.

China’s zero tolerance policy has led to a heavy crackdown on traffickers. Between January and July, 1,238 people were sentenced to either death, life in prison or at least five years in prison, a spokesperson for the Supreme People's Court said. This is 75 per cent more than last year. However, media reports have not indicated how the crackdown has affected the overall problem.

In recent years, media have reported cases involving the abduction of children and the mentally disabled, eventually forced to work, especially in the brick making industry, after being abducted. Police have freed hundreds of such slaves and determined that their captivity was the result of collusion between businesses and local authorities.

Another widespread form of human trafficking is the buying and selling of newborn children, especially for young couples or childless older couples.

In August, Yang Dong, deputy chief of the Criminal Investigation Department, told that the China Daily that between 30,000 to 60,000 children are reported missing every year, but that it is hard to estimate how many of them are trafficking cases.

The situation is especially troubling for the children of migrant workers, who are often handed over to relatives when parents work far from home or even forced to live alone.