A former teammate of Lance Armstrong alleged on TV's 60 Minutes on Sunday that cycling's world governing body had helped the seven-time Tour de France winner cover up a positive drugs test.

Tyler Hamilton told the US version of the show, broadcast on CBS television, that Armstrong had told him he tested positive for EPO (erythropoietin) during the 2001 Tour of Switzerland but escaped punishment after the International Cycling Union (UCI) intervened on his behalf.

Armstrong has always insisted he has never failed a dope test and Hamilton's comments drew an immediate rebuke from Armstrong's lawyer.

Nobody was immediately available at the Swiss-based UCI when Reuters called the headquarters after the broadcast of the US show.

"I know he's had a positive test before," Hamilton said. "He told me. He was so relaxed about it and he kind of said it off the cuff and laughed it off.

"People took care of it. I don't know all the exact details but I know that Lance's people and the people from the other side, the governing body of the sport, figured out a way to make it go away."

Armstrong has always denied taking banned substances and repeatedly fended off accusations he cheated by saying he had never failed a drugs test.

His lawyer, Mark Fabiani, released a statement on Sunday refuting the claims made against him on 60 Minutes.

"Throughout this entire process, CBS has demonstrated a serious lack of journalistic fairness and has elevated sensationalism over responsibility," Fabiani said.

"CBS chose to rely on dubious sources while completely ignoring Lance's nearly 500 clean tests and the hundreds of former teammates and competitors who would have spoken about his work ethic and talent."

During the interview, Hamilton confessed to cheating himself and painted a sordid picture of a doping culture in the sport.

Excerpts of the interview were released last week and Hamilton handed back the gold medal he won at the Athens Olympics following his own admission.

He failed two tests during his career and was investigated at Athens after his 'A' sample came back positive.

He was only allowed to keep his Olympic medal after the laboratory accidentally destroyed his 'B' sample but decided to hand it back after finally owning up.

Hamilton, who had previously denied cheating, said he had decided to come clean after he was subpoenaed by a grand jury investigating Armstrong and was given limited immunity from prosecution for his testimony.

"I feel bad that I had to go here and do this, but I think at the end of the day, long term, the sport's going to be better for it," he said.

In the interview, Hamilton revealed he had used a range of performance enchancing drugs but insisted he was not alone.

He said the practice was widespread but he only named Armstrong, saying he not only used drugs but also helped others to get them through coded messages and secret meetings.

"I reached out to Lance Armstrong ... and he helped me out," Hamilton said.

"It was an illegal doping product, but he helped out a friend.

"I want to make it clear that, you know, if the roles were reversed and I had the connection, I would have done the same thing for Lance."

No charges have been laid against Armstrong, who retired in February, but he has been facing increasing accusations during the federal investigation.