China is executing about 8,000 people every year, almost 20 times as many as the rest of the world combined, a new academic estimate suggests.

Most of the executions are carried out with a bullet to the head, although higher-ranking people in bigger cities are sometimes executed by lethal injection.

The number of executions in China is officially a state secret. But the new estimate from academic specialists, based on information provided by local officials and judges, is likely the most accurate figure yet provided.

The information was disclosed yesterday by Liu Renwen, an expert on criminal law at the Chinese Academy of Social Sciences, who said that he believes it is accurate.

The total number of executions in the rest of the world -- led by Iran, Vietnam, the United States and Saudi Arabia -- is usually about 400 to 500 annually, according to human-rights groups.

Mr. Liu said the number in China has dropped by 50 per cent since a new criminal code was introduced in 1997. But reform of the death-penalty system has been stalled by resistance from local bureaucrats.

China's death-penalty record has come under increasing criticism in recent years, not only from international human-rights groups but also from Chinese legal experts and the Chinese media. There has been growing debate in China on the subject, especially after a recent flurry of revelations that innocent people have been convicted or executed in some cases.

Under China's current system, provincial courts were given the power to decide on executions in 1983 during a national crackdown on crime, and they often feel pressure from local officials who see the death penalty as a deterrent to crime.

For the past two years, China has been planning to allow its highest court to review all death sentences, providing greater scrutiny of any injustices, analysts say. Prime Minister Wen Jiabao promised a year ago that the measure would allow the death penalty to be applied more justly.

But the reform has been delayed by tenacious opposition at the local level, Mr. Liu told journalists yesterday.

While the supreme court has prepared itself to begin reviewing death sentences, local officials are still unwilling to give up their powers, he said.

"It seems that we still need time," he said. "The supreme court is meeting some difficulties in this process. Everyone wants to hold onto his power."

The only reform scheduled for this year is a policy allowing open public trials for death-penalty appeals at the provincial level, Mr. Liu said.

China has also been slow to change its much-criticized system of "re-education through labour," a network of labour camps where thousands of dissidents and other detainees are imprisoned for as long as four years without trial. China promised last year that it would reduce the maximum sentences and make the camps more humane, but the introduction of these reforms could still take several more years, analysts say.

"Reform of the system of 're-education through labour' has ground to a halt," human-rights activist John Kamm said. "We've stopped hearing about it."