Beijing - China has begun a clampdown on companies making drugs that can be used to enhance sporting performance ahead of next month's Olympic Games in Beijing.

Production bans, licence withdrawals and fines have all been used by the authorities, the national anti-doping agency (CHINADA) and other ministerial agencies reported Monday.

According to the reports, 257 companies which deal with or manufacture anabolic steroids and peptide hormones, 2,739 wholesalers and 340,000 consumer outlets were inspected.

As a result, 30 companies were ordered to suspend production while 25 firms had their licence to manufacture drugs which can be used for doping withdrawn.

Another 318 websites, which gave information on the sale of steroids and peptide hormones, were also targeted.

"We have punished those who have broken the rules," said Yan Jiangyung, spokeswomen for the Chinese state authority that overlooks nutrition and medicinal drugs.

Earlier this month, a German television documentary suggested that genetic doping is possible in China.

The documentary broadcast by the state-run ARD network showed a reporter, claiming to be a swimming coach, inquiring about performance- enhancing stem cell treatment for athletes in a Chinese hospital.

While Yan called on the ARD to hand over any information it had on Chinese medical practitioners who were involved in doping, a spokesman for the Health Ministry said genetic doping was not possible.

"I can say in agreement with international experts that such a therapy does not exist in China or elsewhere internationally," said Mao Qunan.

Over 4,500 tests for banned drugs will be carried out on athletes in and around the Beijing Olympics this summer, up on the 3,700 tests carried out in Athens four years ago and a huge increase on the 2,800 at Sydney 2000.

There will be a total of 41 drug-testing stations with every station having at least two labs to improve efficiency. Negative results will be available within 24 hours and positive results within 48 hours.

"The anti-doping measures are not only for the Olympic Games, they will continue into the future," said Yan. (dpa)