Starting from Sunday, parents in Zhejiang province applying for birth certificates for children who were born more than one year before are required to provide paternity test results, according to China National Radio.

The measure was introduced to prevent baby trafficking.

"Normally, parents will apply birth certificates for their newborns as soon as possible. The new regulation will make it more difficult for trafficking babies," Wu Xiangdi, a professor of Sociology at Zhejiang University, told China Daily.

More than 200,000 children are reported missing every year in China. Only 0.1 percent of them are found and returned home again.

However, some have raised objections on issues of privacy.

Whether parents and the child are biologically related is a private matter, said Zhu Wei, a doctorate candidate of law in an online comment.

"What if the baby was not conceived through natural methods? What if one of the parent had cheated on the other and the baby was not their own?"

In China, paternity tests can only be conducted in big cities and they cost about 4,000 yuan ($652).