Mack Horton weighed in as Sun Yang vowed to appeal the ban from the Court of Arbitration for Sport (CAS), who said the eight-years was imposed because the reigning world and Olympic 200m freestyle champion already had an earlier anti-doping rule violation against him from 2014.

"This is unfair. I firmly believe in my innocence," Sun told Xinhua.

"I will definitely appeal to let more people know the truth."

After calling Sun a "drug cheat" at the Rio Games, silver medallist Horton refused to share the podium with the gold medal-winner in Gwangju last year.

Sun had won that race while competing under the shadow of an appeal for smashing vials containing blood samples taken at an out-of-competition test in September 2018.

Horton spoke to Network Seven after learning of this latest sanction against Sun.

"I think regardless of the outcome it was always going to be a statement to the world and my stance has always been about clean sport never about nations or individuals," Horton said.

Some of Horton's fellow swimmers were more forthright with their welcome of the ban.

South African butterfly star Chad Le Clos finished second behind Sun in the 200m freestyle at the Rio Games, but his silver will not be promoted to gold based on the CAS ruling not changing past results..

"Like many other clean swimmers, I have raced against Sun Yang and 'lost'," he posted on Twitter.

"Drug cheats have no place in sport and we need the governing bodies to reconsider the damage he has done to our great sport - and to the results / careers of many other clean swimmers."

British Olympic and world 100m breaststroke champion Adam Peaty said the decision was "very good".

"For anyone that's been banned once, potentially it's a mistake. The odds are yeah - you could have taken any supplement or whatever," he told Swimming World.

"You're looking at it twice - you're a fool. I believe that you're disrespecting the sport, you're disrespecting yourself and you're disrespecting your country."

The case has attracted huge interest in China, where Sun is currently training at the Zhejiang College of Sports in Hangzhou, and the swimming world.

A FINA report said Sun questioned the credentials of the testers before members of his entourage smashed the vials with a hammer.

Sun had argued during the CAS hearing, which was heard in public, that the testers failed to prove their identity and behaved in an unprofessional manner.

"The CAS Panel unanimously determined, to its comfortable satisfaction, that the athlete violated Article 2.5 FINA DC (Tampering with any part of Doping Control)," the CAS statement said.

"More specifically, the athlete failed to establish that he had a compelling justification to destroy his sample collection containers and forego the doping control when, in his opinion, the collection protocol was not in compliance with the ISTI."

The statement added that it was "one thing, having provided a blood sample, to question the accreditation of the testing personnel while keeping the intact samples in the possession of the testing authorities.

"It is quite another thing, after lengthy exchanges and warnings as to the consequences, to act in such a way that results in destroying the sample containers, thereby eliminating any chance of testing the sample at a later stage."

WADA welcomed the ruling as "a significant result" in a separate statement and said it was "satisfied that justice in this case has been rendered".

Australian Associated Press