The official from the Chinese Olympic Committee (COC) Anti-Doping Commission, who did not want to give his name, said suggestions or well-grounded criticisms could help them improve on their work.

"We are not afraid of criticisms, as long as they are well intended, because we truly want to catch cheaters who use drugs," the official said.

"I know this has been repeated many times, but I still want to say that China firmly opposes doping, and this is not something we just say. It is what we have done for a long time."

China started administering doping tests in 1990, when 165 tests were conducted, with 1.82 percent of the results turning out positive.

Last year, China's anti-doping lab, now part of the new China Anti-Doping Agency, conducted 10,238 dope tests, returning 15 positive results.

To ensure a clean team for the Aug 8-24 Games, China has conducted 6,038 doping tests, 85 percent of which were out-of-competition, by June 30. In July, the COC announced eight positive results, and two national team athletes and their coaches were issued lifetime bans.

"Some reports just made me very uncomfortable and upset - not because they were critical but rather, because they were untrue," the COC official said.

On Thursday, the Ministry of Health said China has never approved any hospital to provide performance-enhancing stem-cell therapy. The comment was in response to a German TV report that some Chinese clinics claimed to be able to provide what had been described as "gene-therapy treatment" for athletes.

"I am not in a position to comment on supervision over hospitals or control on drug production, but I can certainly see the government is determined to crack down on doping," he said.

"The war against doping, however, is not one that can be won overnight."

The government issued an anti-doping law in March 2004, before a coordination group comprising 11 major government departments was created last year to tackle the problem.

Over the past two years, the country had launched several special investigations into performance-enhancing drugs to ensure a fair Olympics.

In these campaigns, 23 companies were punished for engaging in illegal drug trading or selling performance enhancers that should not have been available over the counter since last year.

In addition, three drug-makers were ordered to suspend production of relevant drugs, while another 18 had their licenses revoked. Similarly, 321 websites with illegal drug trading information were closed.