SYDNEY, April 22, 2024 (BSS/AFP) - A veteran Australian coach who works with the Chinese Swimming Association has rejected claims of systemic state-run doping, insisting it is "so far from anything I have seen".

The sport was rocked at the weekend by revelations that 23 Chinese swimmers tested positive for prescription heart drug trimetazidine (TMZ) -- which can enhance performance -- ahead of the Tokyo Olympics in 2021.

But they were allowed to compete after world governing bodies secretly accepted China's findings that they had ingested it unwittingly from food during a meet in late 2020 and the early days of 2021.

Several went on to win medals, including gold, and are in line to compete at the Paris Olympics this summer.

Denis Cotterell, who steered Australian Grant Hackett to multiple Olympic gold medals and also coached drug-tainted Chinese swimmer Sun Yang, told the Sydney Morning Herald he disputed "any suggestion of anything orchestrated".

"Am I confident that it's not dastardly? Not for one minute (do I believe that). I wouldn't be here (if it was)," Cotterell told the newspaper by phone from the pool deck of the Chinese Olympics trials in Shenzhen, in comments published Monday.

"I am happy to say I'm absolutely in support of my swimmers and dispute any suggestion of anything orchestrated."

World anti-doping agency WADA said there was "a lack of any credible evidence" to challenge China's version of events.

However, the United States Anti-Doping Agency called news of the failed tests "crushing" and blasted WADA's lack of action as "a devastating stab in the back of clean athletes".

Cotterell, who has had an on-and-off association with Chinese swimming for more than a decade, said he was speaking from first hand experience.

"I see what they go through. I see the measures. I can tell you the stories. I know the facts and I am comfortable," he said.

"The suggestion that it's systemic is so far from anything I have seen here the whole time.

"That suspicion was unfortunately earned from 30 years ago in the 1990s. They are so adamant on having clean sport."

China's anti-doping authority and swimming association have yet to publically comment.

Cotterell said he was not authorised to speak on their behalf and was "on a hiding to nothing" by giving an interview.

But the 74-year-old said he wanted to fight for the integrity of himself and Chinese swimming.

"I can understand if they (other athletes) are (upset), that's their prerogative," he said.

"I sympathise on other fronts for other reasons. How it was handled, that's the point of conjecture. I know what they have to endure here.

"It's sad that their names (the swimmers) are caught up in unfortunate circumstances beyond their control. How that's handled, well, that's beyond their control. I feel for the athletes."