Hong Kong ( CNN ) -- China 's move to abolish re-education through labor camps -- under which tens of thousands have been imprisoned without trial -- may be no more than a cosmetic change , a new report from Amnesty International warns . The human rights group says that while labor camps are being shut , research suggested that authorities are expanding the use of `` black jails , '' enforced drug rehabilitation clinics and `` brainwashing centers '' to take their place . `` There is a very real risk that the Chinese authorities will abolish one system of arbitrary detention only to expand the use of other types , '' the report said . A spokesman from China 's Ministry of Justice declined to comment on the Amnesty report . Corinna-Barbara Francis , Amnesty International 's China researcher , said the abolishment may only be a `` cosmetic change just to avert the public outcry over the abusive re-education through labor system . '' China said on November 15 that it would close its labor camps after earlier putting the policy under review , with the move hailed as the biggest change to China 's criminal justice system in decades . Detention without trial . The system was set up in 1950s and allows police to detain petty offenders -- such as thieves , prostitutes and drug addicts -- for up to four years without a trial . According to China 's Ministry of Justice , the country had 351 labor camps at the end of 2012 , with more than 50,000 inmates . Other estimates have put the number of detainees much higher . The `` re-education process '' has also been used to punish those detained for their political , religious or personal beliefs -- such as members of the banned Falun Gong spiritual movement or petitioners with complaints against local officials , Amnesty said . Torture is said to be rife at the camps . Detainees have told Amnesty International they were beaten , sometimes with electric batons , denied food , subjected to simulated drowning , injected with unknown drugs and subjected to the `` rack '' torture . '' Brainwashing centers . The report said interviews with petitioners and Falun Gong practitioners revealed abuses were continuing despite the closure of the camps . Some labor camps were being re-labeled as drug rehabilitation centers and released detainees were being sent to black jails -- unofficial detention centers set up in places like hotels or abandoned buildings -- or `` brainwashing centers , '' another form of arbitrary detention . Falun Gong practitioner Zhang Zhi told Amnesty International she was released from a labor camp in Harbin in June 2013 but on her release staff from a brainwashing center were waiting for her at the gate . Her family were able to intervene and prevented her from being taken away . She has since gone into hiding . `` The Chinese authorities must immediately end all forms of arbitrary detention and ensure that laws protecting detainees are brought into line with international human rights standards , '' Francis said . `` This needs to be a fundamental change in the policies that are at the root of the repression and which strip detainees of their most basic rights . ''
Amnesty says China 's move to open labor camps may be a cosmetic change . Rights groups say Chinese authorities are expanding use of other types of arbitrary detention . China said on November 6 that it would end its labor camp system . China : Chinese government declines to comment on the report .