China cast a drugs cloud over the World Championships yesterday after insisting their team would not be withdrawn despite a swimmer and coach being charged with drug trafficking.

The Chinese received international condemnation after incredulously claiming vials containing human growth hormones discovered in a random search on Thursday were brought for someone living in Australia.

Swimmer Yuan Yuan and her coach, Zhou Zhewen, have been charged with trafficking an illegal performance-enhancing drug by FINA, swimming's world governing body, and each face bans of at least four years.

But the rest of the team have been cleared to compete in the championships, which get under way in Perth's Challenge Stadium on Monday, despite calls for them to be sent home in disgrace.

And with China's women swimmers expected to reap a rich harvest of medals, it will inevitably leave a pall of suspicion and doubt hanging over the seven days of competition.

Even if they suddenly fail to live up to their world rankings, it will only raise speculation that they have been ordered to lose by sports officials back in Beijing.

"We are very sorry that two of our members made some mistake in their customs declaration," said Shi Tianshu, China's chef de mission, in Perth yesterday. "The Chinese swimming delegation attach great importance to this matter. It is very serious."

But Shi added: "According to the swimmer's coach, before he left China someone asked him to take a certain substance to Australia and give it to some other people inside Australia. I don't know who those people are.

"We have come here with 23 swimmers and 12 coaches. But if one or two people make a mistake, you cannot regard that individual behaviour as a collective one.

"If we found anyone on our team using doping substances, we would take very strong measures against them and they would be severely punished. The Chinese federation have always fought against doping."

The official said over 600 tests had been carried out on Chinese swimmers last year with no positive results, although growth hormones - which are produced naturally by the body - cannot be detected by current equipment.

A flask containing the hormone, somatropin, was only discovered when Australian customs officials conducted a search of Yuan's baggage in Sydney on Thursday during a stop-over en route to Perth.

Two independent tests were conducted yesterday - one by the Australian Government Analytical Laboratories (AGAL) and the other by a specialist hormone laboratory - and they confirmed the nature of the drug.

Yuan, a silver medallist in the 1994 World Championships, and her coach have been ordered home by Chinese state sports officials, but not before they face a FINA doping panel in the next couple of days.

The FINA bureau met for two hours yesterday and questioned Chinese officials. Secretary Gunnar Werner said: "It was decided not to take any action against the whole Chinese team as we have not found any reason to do that.

"Trafficking of the growth hormone contravenes FINA's rules and the bureau have decided to refer the case to the doping panel with action to be taken under FINA rules."

Werner confirmed the entire Chinese team had been drugtested at the championships - including Yuan, who has not been accredited - and said he expected the results to be known within 24 hours. But he also admitted growth hormones could not be detected even if blood samples, rather than urine samples, were used.

Australian coach Forbes Carlile called for the Chinese team to be told to leave Perth. "I don't see how they can be allowed to stay," he said. "The whole team are implicated." Renewed fears about China's use of drugs were raised by a series of record-breaking performances and 1997 world best times at the National Championships in Shanghai last October.

China's women could win 10 of a possible 16 gold medals if they live up to their world rankings, which, in many people's eyes, would turn the eighth World Championships into a farce.