Using stem-cell therapy to enhance an athlete's performance is technically impossible at present, Ministry of Health officials said Monday.

They said foreign media reports that some Chinese hospitals are offering gene doping to athletes to achieve better performances are not true.

"I learned from experts that using stem-cell therapy to enhance an athlete's performance is not possible at present, both in China and in other countries," Mao Qun'an, a Ministry of Health spokesman, said.

"In China, only a few hospitals are able to transplant hematopoietic stem cells, which are strictly used for some blood diseases. We hope the media can give the public a clear understanding of this," he said.

Recently, a documentary by Germany's state-run ARD network, showed a Chinese doctor offering stem-cell therapy to a reporter posing as an American swimming coach. But the documentary did not name the doctor or the hospital.

"The Ministry of Health has never approved any organization to offer co-called 'stem-cell doping therapy' and we do not allow any organization or doctor to offer such therapy," Mao said.

"If any of such illegal activity is found, severe punishment will be meted out."

In the lead up to the Beijing Games, which is only 10 days away, the government has been boosting its anti-doping campaign.

The State Food and Drug Administration has taken a series of measures to control the manufacture of drugs and stimulants.

The measures include assigning inspectors to more than 80 drug manufacturers producing anabolic agents and peptide hormones. All drugs containing stimulants are required to be marked with warning labels.

Sports authorities have introduced more severe punishment for athletes to express their zero-tolerance of doping.

"According to a new regulation on anti-doping issued by the State General Administration of Sport in March, any national team athlete who is tested positive will receive a lifetime ban," Du Lijun, director of China Anti-Doping Agency, said.

"Our objective is to make sure all Chinese athletes will have a clean Olympic Games."

Eight positive doping cases were uncovered by Du's agency in the first half of this year. They included two national team athletes - backstroke swimmer Ouyang Kunpeng and wrestler Luo Meng. Both have received lifetime bans. During the Games, a record high 4,500 doping tests will be conducted.