ZHENGZHOU, Feb. 14 -- Authorities in central China are looking into charges that residents looking to petition the government have been held and mistreated in local "discipline centers."

Nine supervision groups and two undercover investigation teams were dispatched on Friday by the government of Henan Province to investigate into the matter.

Posts appeared Thursday on Sina Weibo, China's equivalent of Twitter, said some petitioners were illegally held at discipline centers. Netizens questioned if these centers are another form of reform through labor, which has been abolished by the Chinese government.

The Henan government said such centers, if found, will be closed and any illegal acts will be punished according to law. Officials sent to probe into the case include officials from the provincial department of public security and the Henan Bureau for Letters and Calls (HBLC).

"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.

Petitioning, also known as "letters and calls" is China's administrative system for hearing complaints and grievances from members of the public. It often involves groups traveling to the seat of government in Beijing.

Discipline centers were once used to educate Beijing-bound petitioners not going through the proper channels, but most cities and counties in Henan have stopped using them, sources with the HBLC said, while admitting that the centers still operate in some areas despite a government ban.

Officials with the HBLC said that they will not tolerate such illegal acts, adding that they will improve work under the supervision of the general public to guarantee people's legitimate rights while ensuring social stability.