Authorities in central China are looking into media reports that petitioners have been held and mistreated in local "discipline centers".

Nine supervision groups and two undercover teams from the provincial department of public security and the Henan Bureau for Letters and Calls were dispatched on Friday by the Henan provincial government to investigate.

"The investigation is a step toward ramping up media and societal supervision, as well as ironing out defects in the petitioning system," said a source with the government.

Media reported earlier this week that some city and county governments in Henan province illegally detained petitioners they deemed "irregular" — those who act outside of regulated petition procedures.

In response, the provincial government said in a statement posted on its website on Thursday that they had asked the involved governments to close the illegal centers, if found, after a "thorough investigation".

There are worries that such centers are used to enforce the laojiao system, or re-education through labor, a system that was abolished during the Third Plenary Session of the 18th Communist Party of China Central Committee in November.

A petitioner is someone who comes to higher authorities, mostly in big cities, to express their opinions and file grievances.

An unnamed official from the provincial petition bureau admitted that some local authorities, including public security and justice departments, had been required to educate people who go to Beijing to petition since 2008.

Some forms of education were carried out in the petitioners' homes and workplaces, while other forms of education were conducted through the discipline centers. The official said most of the centers have been closed in recent years, but some city and county governments still operate them.

Officials with the provincial petition bureau said that they will not tolerate such illegal acts and vowed to wipe out every illegal center across the province.

Cheng Lei, an associate law professor at Renmin University of China, called on governments in other areas to learn from dealing with petitions.

While the laojiao system was valid from 1957 to November 2013, the detention centers for petitioners have always been illegal and known as "black jails", he said.

"The centers deprive a person of their freedom and could make a comeback if governments pay more attention to social stability instead of solving disputes."

Zhao Li, a lawyer in Beijing who specializes in criminal cases, added that the centers were not only in Henan and that other governments must be alerted.

Previously, some governments rented rooms to "block" petitioners who came to Beijing to resolve disputes that could not be resolved in their hometowns, Zhao said, adding that their performance was ranked by how many petitioners they stopped.

But this ranking system has been canceled, he said.

"The money used to pay those responsible for detaining petitioners and to rent rooms to detain them should go toward solving residents' problems," he said.

"A river flows by dredging instead of blindly cutting off streams. Similarly, rooting out petitions lies in communication between officials and residents," he added.

Yang Weidong, a professor at the Chinese Academy of Governance, agreed, saying the illegal centers may become the new laojiao places, if governments do not wipe them out.

Since the laojiao system was abolished, many governments have released those detained and have been exploring ways to transform the former re-education centers, Yang said.

"But some governments like those in Henan did not transition smoothly, so any illegal centers that may exist must be killed in cradle," he said. "Our judicial bodies and petition authorities should provide channels for residents to speak out their discontent and disagreements."

For petitions caused by unjust trials, courts are responsible, while for those caused by social problems, such as demolitions, local petition bureaus should inform residents of solutions, he said.