Beijing, Feb 28 (AFP) China's triple Olympic swimming champion Sun Yang vowed to appeal on Friday after he received an eight-year ban for refusing to give a doping sample, saying he was "shocked" and "angry".

"This is unfair. I firmly believe in my innocence," Sun told China's Xinhua news agency soon after the judgement by the Court of Arbitration for Sport (CAS).

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

In a statement on Weibo, China's version of Twitter, the 28-year-old repeated his defence that the doping testers who went to his home in September 2018 were not qualified.

"Let more people know the truth," added Sun, who served a three-month doping ban in 2014.

"I believe in my innocence! Believe in the truth and defeat the lie!"

Thanking China's sports authorities and his supporters -- he is hugely popular in China -- Sun said: "I will fight to the end to defend my legitimate rights and interests!"

The Chinese Swimming Association (CSA) said "we deeply regret the decision of CAS" and echoed Sun's assertion of events in 2018, when a vial of his blood was smashed with a hammer.

The CSA said the testers were "personnel without professional training and legal qualification to collect athlete samples, and the activity was illegal and invalid".

"We support Sun Yang to continue to safeguard his legitimate rights and interests by legal means," it said.

The severity of the ban handed out to Sun, the 1500m freestyle world record-holder, was greeted with disbelief by his fans.

His punishment was trending on Weibo with at least 290 million views.

"What conspiracy is this? It's too much," wrote one Weibo user.

"Eight years... is an athlete's professional career," commented another. (AFP)

(This is an unedited and auto-generated story from Syndicated News feed, LatestLY Staff may not have modified or edited the content body)