China is introducing a new policy starting March 1 which prohibits the use of torture to extract confessions.
The Law on Penalties for Offences against Public Order would also bar evidence obtained with threats from being used to pursue prosecutions.
Ke Liangdong, Director of the Legal Affairs Bureau of the Ministry of Public Security, was quoted as saying that the law stipulated an "illegal evidence exclusion principle", which said that "evidence obtained by torture, threatening or cheating could not be used as the basis for penalties".
Police brutality is common in China despite clear regulations and guidelines on detention and interrogation procedures.
Local media have reported that police investigators had found 12,000 cases of inappropriate handling of detainees in 2005.
In one case reported recently, a newspaper editor who was severely beaten by police, died from multiple injuries.