Tennis great Andre Agassi's upcoming autobiography contains an admission that he used crystal meth in 1997. Photo / AP

Tennis great Andre Agassi's upcoming autobiography contains an admission that he used crystal meth in 1997. Photo / AP

Leading tennis players from the mens and womens professional circuit have come out in condemnation of Andre Agassi's revelations about drug use and a subsequent cover-up.

Former World No.1 Rafael Nadal said today it would be "dreadful" if tennis authorities covered up Agassi's drug habit.

Agassi's upcoming autobiography contains an admission he used crystal methamphetamine in 1997 and failed a drug test.

The 39-year-old went on to say he'd lied to Association of Tennis Professionals (ATP) officials to escape a penalty for using the banned stimulant.

Nadal said if the ATP had known about Agassi's drug taking and protected him it would be unacceptable.

"If the ATP covered for Agassi at the time then I think that's dreadful," Nadal said in Madrid as he prepared to receive a civic award.

"The only thing I can say is that if they covered at that moment for the player and punished others for doing the same kind of thing then that would seem to me to be a lack of respect for all sportsmen."

On being told he had tested positive for the banned stimulant, Agassi said he wrote a letter to the ATP, claiming he had taken it by accident and asking for leniency.

No disciplinary action was taken.

Since the story came to light, World Anti-Doping Agency (WADA) president John Fahey has asked ATP chiefs to "shed light" on the issue.

Crystal Meth is on WADA's List of Prohibited Substances and Methods.

The World Anti-Doping Code only took effect in 2004 and has an eight-year statute of limitations.

But Fahey said that WADA would expect the ATP, which administered its own anti-doping programme at that time, to shed light on the story.

Nadal concluded that "cheats have to be punished" and said he could not understand why Agassi "now that he is retired comes out and says this - it's a way of senselessly damaging the sport".

Grand Slam champions Martina Navratilova and Marat Safin said Agassi should have owned up to a positive drug test when it happened - 12 years ago.

"Shocking," Navratilova told the Associated Press from Florida in a phone interview today. "Not as much shock that he did it as shock he lied about it and didn't own up to it. He owned up to it (in the book), but it doesn't help now."