Lance Armstrong's lawyers sought an apology on Wednesday and instead received a rebuke from US television network CBS over a story on doping claims against the seven-time Tour de France winner.

Attorney Elliot Peters denigrated last month's story on '60 Minutes', which centered on an interview with former Armstrong teammate Tyler Hamilton, in a letter to CBS News chairman Jeff Fager, the show's executive producer.

"In the cold light of morning your story was either extraordinarily shoddy, to the point of being reckless and unprofessional, or a vicious hit-and-run job," Peters wrote. "In either case, a categorical on-air apology is required."

Fager defended the story and said CBS awaits Armstrong responding with more than a Twitter post to the claims of Hamilton and others from ex-Armstrong teammate George Hincapie cited by unnamed sources in the report.

"'Sixty Minutes' stands by its story as truthful, accurate and fair," Fager said. "Lance Armstrong and his lawyers were given numerous opportunities to respond to every detail of our reporting for weeks prior to the broadcast and their written responses were fairly and accurately included in the story.

"Mr Armstrong still has not addressed charges by teammates Tyler Hamilton and George Hincapie that he used performance enhancing drugs with them."

The exchange came in the wake of a Swiss laboratory director, Martial Saugy, denying Armstrong tested positive for a banned substance in the 2001 Tour of Switzerland.

Saugy has since said there were suspicious levels of EPO (erythropoietin), a banned endurance booster, in four samples from the race but he could not be certain that any of them belonged to Armstrong.

The report also said there was a meeting between Saugy and Armstrong and his former team manager, Johan Bruyneel, regarding the suspicious test and doping protocols. Saugy says the meeting was not connected to any test result.

Peters also said CBS was told before the show aired that allegations regarding the Swiss race were untrue.

"What is particularly disturbing is that '60 Minutes' had access to the true facts, could easily have verified them and apparently chose instead to broadcast untruths and then layer innuendo on top of the falsehoods," Peters said.

In his statement, Fager noted a letter to CBS from Armstrong's attorneys claimed there was no "positive" or "suspicious" test from the 2001 Swiss race when the report cited Hamilton and several officials linking Armstrong to the "suspicious" result.

Fager also said Saugy recalled a meeting with Armstrong and Bruyneel after the report but Armstrong said he did not recall such a meeting.

Fager also scoffed at Peters' claim of "shoddy" work when the original letter from Armstrong's lawyers to CBS was wrong about the CBS report claiming the meeting was secret, at the Swiss lab and in 2001.

David Howman, World Anti-Doping Agency director, told CBS in the report that any meeting involving Armstrong, Brunyeel and Saugy would be "highly unusual" and "inappropriate".

Armstrong has denied doping allegations, including those raised by former teammates and admitted dope cheats Floyd Landis and Hamilton, who claimed in the CBS report Armstrong used EPO in preparing for the 2001 Tour de France and that the International Cycling Union (UCI) played a role in keeping a positive test at the 2001 Swiss race a secret.

US investigators are looking into Armstrong as part of a probe into doping in cycling.

Evidence of a positive drug test from Armstrong, who has denied ever testing positive for doping, could open the door for potential liabilities from fraudulent claims made to such former US cycling sponsors as the US Postal Service, which backed Armstrong's racing squad for many years.