As China scrapped its one-child policy, the existing social tracking system - a sort of credit rating for parents - was expanded in southern Guangdong province to help deter a third baby.

Now, the reports will indicate that a couple has exceeded the limit.

Couples who have a third child in violation of the rules will have difficulty applying for a loan, buying an airline ticket or benefiting from other social services under Guangdong's amended family planning regulation.

The rule was approved by the provincial legislature on Dec 30, three days after the top national legislature approved the two-child rule. The province, which has a reputation for bigger families, was the first to add number of children to its social credit reporting system at the local level.

Children born in violation of the rule will have hukou, or household registration, and can attend school. But their parents will face barriers in receiving some services going forward.

The current social maintenance fee will remain in place for births that exceed the legal limit. If the parents pay the fee, they will face no barriers.

"In a new era moving gradually toward giving birth rights to families, past punitive measures, administrative management and barriers based on residency permits, or hukou, will lose power," said Yuan Xin, an expert in population studies at Nankai University in Tianjin.

So new tools like the social credit report will be used to facilitate government's task of managing demographic development, including averting law-violating extra births, Yuan said.

Under the new law, couples no longer need to ask for a birth permit beforehand for two children, though they are required to report and register their newborns.

Also, unlike in the past, hukou, which is necessary for a child to access public services such as schooling will no longer be used as a screening tool to punish births that breach the law.

While violators are subject to the ongoing social maintenance fee, "it will definitely be much harder to collect without the past teeth," Yuan said.