Chinese ambassador Li Baodong told the U.N. Committee Against Torture in Geneva that his country expressly forbids torture and has introduced strict laws to punish all who intimidate, harrass and injure those in state custody.

But activists observing the review said that the 32-member Chinese delegation skirted questions about the prevalence of abuse in police stations, prisons, informal custody houses, psychiatric hospitals and other facilities.

"The Chinese delegation as a whole has not given data on enforcement, they have given data on the formal law," said Sharon Hom of the New York-based Human Rights In China.

Hom said that because Beijing classifies statistics about unusual deaths in prison and other criminal justice information as state secrets, it is nearly impossible for outsiders to know how extensive violations are.

"We cannot do an accurate, complete assessment if there is not accurate, transparent, reliable data," she told reporters after the two-day review ended. "However, what is on the table now is a very full list of important issues."

The Committee's 10 independent experts pressed China to reveal information about alleged cases of mistreatment of human rights lawyers, followers of Falun Gong spiritualism, drug addicts, and critics of the Beijing government.

They also sought details about China's crackdown in Tibet after demonstrations there in March, including reports that people died or were brutally attacked in Chinese custody.

Delegation leader Li rejected as "groundless and untrue" many allegations raised by Chinese and Western activist groups ahead of the review, dismissing them as "baseless information from organisations with ulterior motives".

"We have zero tolerance for torture," he told the panel, which monitors countries' compliance with the U.N. Convention Against Torture that China ratified in 1988.

"We have made large-scale judicial reforms to strictly regulate the law enforcement conduct of our judicial personnel."