While his coach claimed Justin Gatlin's positive drug test was a result of sabotage, the leader of the World Anti-Doping Agency today called for the American sprinter to be banned for "up to life" if the results are confirmed.

Gatlin's coach, Trevor Graham, said in an interview on Jamaican television the Olympic and world champion and co-world record-holder in the 100 metres was a victim of a set-up.

"We are 100 per cent sure who it is," Graham said.

"The individual that did it, it's an individual that we fired and we went back and hired ... he came to the Kansas relay and was (upset) with Justin."

On Saturday, Gatlin acknowledged he had been informed by the US Anti-Doping Agency he had tested positive for testosterone or other steroids after a relay race in Kansas in April.

The revelation came just days after Tour de France champion Floyd Landis' victory was thrown into question for allegations of similar violations.

Gatlin said he did not know why the test came back positive and promised cooperation with USADA, as it continues with the case.

Gatlin's connection with Graham, however, is viewed as problematic. Gatlin has long positioned himself as a champion of drug-free competition in a sport dogged by problems, while Graham is a key figure in the BALCO investigation and has coached several athletes who have tested positive for steroids.

Gatlin's attorney, Cameron Myler, said she and the sprinter had ideas about how his drug tests came up positive, but she would not get into details and said she did not condone Graham's allegations.

If Gatlin is proven guilty, his world record would be stripped.

He tied Jamaican Asafa Powell's mark (9.77 seconds) in the 100 metres in May, after the positive test. Gatlin would also be banned for life, the standard discipline for a second positive test.

The head of WADA, Dick Pound, called for such a penalty.

"He needs to be banned for up to life," Pound said in an interview on BBC Radio Five Live.

"There may be some extenuating circumstances to come out but I think if he just continues to come out with some bland denial that 'I never did anything, I can't imagine how this result occurred,' that will not help him when it comes to sentencing.

"If they can find someone who did, in fact, spike it, then it is for them to prove but short of something like that I think he has a very serious problem."

WADA bylaws do provide relief for accused athletes who can prove they have been victims of sabotage, although the burden of proof is steep.

The International Association of Athletics Federation said in a statement today Gatlin will be suspended for life if his positive drug tests - both his 'A' and 'B' samples came back positive - are confirmed.

Gatlin was suspended for two years in 2001 after testing for illegal substances, the result of taking medication to control attention deficit disorder.

AP