The Ministry of Public Security has promised to take action to improve murder investigations and prevent abuses during interrogation.

Speaking at a press conference, He Ting, director of the ministry's criminal investigation bureau, said that police from all parts of the country would be encouraged to videotape all murder case interrogations, a practice already standard in eastern coastal regions such as Shanghai and Jiangsu.

"We did not make it obligatory, because police bureaus in some poor western areas cannot afford the recording equipment," He added.

Prosecution departments, which operate independently of the police, will ask detainees to sign a form to say whether they have been forced into making confessions. A special room will be set up in all police stations for prosecutors, the ministry said.

In addition, the ministry has requested local police bureaus to issue a public report each month on the progress of murder investigations.

"Police must guarantee the quality of their work, and punish criminals and not innocent people," He reiterated.

Last year, China freed a man named She Xianglin, who spent 11 years in jail for allegedly murdering his wife, after the woman turned up alive.

In another case last June, the children of a butcher named Teng Xingshan, who was executed for murdering a waitress, appealed against his conviction after the woman returned home alive.

"There have been some unjust cases in the past few years, " He admitted. "But they were very rare."

"We have taken measures against the practice of forced confessions, and no such cases have been discovered recently."

He said violators would be punished severely according to law, but he did not mention what the punishments were.

The ministry also revealed that about 90 per cent of 31,000 murder cases last year were solved, higher than 63 per cent in the United States and 87 per cent in Britain.

And the number of murder cases per 100,000 population was 2.39, far less than the 5.6 in the United States, for example.

"This is due to good police work," He said, "We place murder cases as our top priority, as such cases greatly jeopardize social stability."

"But to achieve the goal set in 2004 that each murder case must be solved, further efforts are needed."

In China there are eight categories of murder manslaughter, intentional injury, explosion, poisoning, arson, robbery, rape and kidnapping cases that involve the killing of a person.

Ministry figures show that about 66.7 per cent of the total murder cases were manslaughter, and more than 60 per cent of the cases were caused by civil disputes such as divorce or neighbourhood quarrels.

And the eastern coastal regions witnessed more murder cases than the western areas, something the ministry blamed on uneven economic development.