The ugly issue of drugs at the Olympics was on and off the agenda in Sydney yesterday with the greatest sporting show on earth just three days away.

The International Olympic Committee has boasted of its strongest clampdown in the build-up to the Games - but officials admitted testers were having problems with its programme.

Olympians at pre-Games training camps around Australia have resorted to locking their apartment doors when the drug testers hit town, one official said.

Australian Sports Drug Agency (ASDA) spokeswoman Vicki Kapernick confirmed not all competitors had been co-operative, but refused to discuss specific cases.

"Some have done some interesting things," Kapernick said, adding that sampling officers have filed reports on a number of incidents without elaborating.

"It's been an interesting time for us, and I think we've done pretty well," Kapernick said.

China, still reeling from a scandal that saw 27 athletes booted off the team last week, were at pains to avoid doping talk when they arrived at the athletes village.

Officials were eager to avoid use of the word "drugs" when questioned about their decision to leave behind 27 athletes because of "suspicious blood test results". The chief of the Chinese delegation, Yu Zaiqing, denied speculation that the clean-up was directly linked to Beijing's 2008 Olympic bid.

"It is the city that bids for Olympics. We are a national Olympic committee," Yu said. "Even if there is an image problem that matters in the area, we are doing nothing about it as a country."

Yu's words came as Australian swimming coach Don Talbot - one of the most outspoken critics of drugs in sport - opted to stay silent on the doping issue.

Talbot has told his swimmers not to answer questions on doping and declined to comment on Susie O'Neill's controversial assertion earlier this year that Dutch swimming sensation Inge de Bruijn's recent world records were "pretty suss".

Talbot was the perfect diplomat, however, when he said: "It's something we shouldn't be thinking about. I've told the team not to think about it. It's out of our control."

But while China and the host nation's swimming team appeared anxious to keep dope talk off the agenda, IOC vice-president and World Anti-Doping Agency (WADA) chief Dick Pound was less reticent.

Pound launched a blistering attack on the International Amateur Athletics Federation (IAAF), the sport's governing body, for its decision to allow Cuban high jumper Javier Sotomayor to compete in Sydney after slashing a ban for cocaine use.

Canadian lawyer Pound, tipped by many as a leading candidate to succeed Juan Antonio Samaranch as IOC president, was blunt when quizzed on the IAAF's decision to allow Sotomayor to compete.

"A lot of people were surprised at the lifting of the ban and you can count me as one of them," said Pound.

"He had been convicted and should have served the full two-year ban. I don't know why the IAAF did it."

Meanwhile, as more athletes flooded into Sydney yesterday, rumour and gossip continued to swirl around the identity of who will have the honour of taking the last leg on the torch relay and igniting the Olympic flame.

Traditionally it is a great Olympian of yesteryear from the host nation that gets the accolade and Sydney knows that they will be hard pushed to match Atlanta's choice of boxing legend Muhammad Ali four-years ago.

Swimming legend Dawn Fraser and wheelchair-bound former gold medal winning athlete Betty Cuthbert are the bookmakers favourites although non-Olympian Australian heroes such as cricket legend Don Bradman and Greg Norman are also in the frame.

No less than 3,000 Olympic-related travellers arrived at Sydney airport yesterday - the biggest influx yet for one day. That means 28,000 of the 41,000-strong Olympics entourage - competitors, media and other "industries" are now in Sydney.

The numbers of Olympic visitors are now reaching critical point and yesterday was the last "normal" day for Sydneysiders who will go on full Olympic red alert today when the transport programme goes into full swing.

The highest profile arrival in Australia yesterday was American athlete Marion Jones, who is bidding for a haul of five gold medals. She is setting up camp in Melbourne.

But while Sydney may be ready for the Games, the same cannot be said for Athens, who will stage the 2004 Olympics.

Belgian IOC member Jacques Rogge - another fancied candidate for Samaranch's job - gave the latest public kick up the backside to the Greek capital at a press call in Sydney when he brought forward construction deadlines by six months.

"The clock is ticking," warned Rogge.