The Chinese government will advance reforms for its controversial re-education through labor system this year, according to a national political and legal work conference held on Monday.

The system allows police to detain people for up to four years without an open trial, leading experts to argue that it contradicts high-level laws, including China's constitution.

No further information on the reforms has been made available.

Public criticism of the system has mounted following two recent cases.

Last month, a court in southwest China's Chongqing municipality rejected an appeal from Ren Jianyu, a 25-year-old village official who was sentenced to two years in a re-education through labor camp in September 2011 for spreading "negative information" and inciting the subversion of state power.

Related story: Court rejects village official's labor camp appeal

Last August, a woman in central China's Hunan province was sentenced to 18 months in a labor camp after demanding tougher penalties for seven men who were convicted of abducting, raping and prostituting her 11-year-old daughter.

Tang Hui, a crusading mother who petitioned courts and local government officials for tougher penalties for her daughter's captors, was released within a week following complaints from academics, state media and the public.

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According to the Bureau of Re-education Through Labor under the Ministry of Justice, 160,000 people were imprisoned in 350 re-education through labor centers nationwide as of the end of 2008.

Jiang Wei, a senior official in charge of judicial reforms, said last October that the necessity of the reforms had been recognized and a related plan was being formulated.