Chinese state-run media called Wednesday for children born outside the country's one-child policy to be given crucial household registration documents, an issue that has left as many as 13 million in legal limbo.

A "hukou" registration is essential in China to obtain basic social services such as schooling, healthcare and housing.

Parents who violate the policy, which limited most to a single offspring but is to be replaced with a two-child rule for all, can only register extra children after paying a hefty fee.

Many working families cannot afford the cost, with the government-published China Daily saying in an editorial that such children should be allowed to access the social services.

"These children are innocent of any wrongdoing and they should be granted the legal status that would enable them to access social resources," the editorial said.

The end of the one-child policy, announced last month, has provoked a national conversation about its impact on Chinese families.

A Beijing woman, Li Xue, told AFP last month how she has been forced to live in the shadows due to the bureaucratic requirements.

Her family was required to pay 5,000 yuan -- far beyond the 100 yuan a month in benefits that her parents lived off.

"We'd have to go to the neighbours to beg for some medicine if she was sick," her mother said.

The Ministry of Public Security promised Monday it would address the problem of children who are unable to secure a "hukou", according to reports.

Authorities had previously promised to reform the system, but little progress had been made.

"Local authorities should reflect on how to carry out government policies without violating a person's legal rights," the China Daily editorial added.