The International Olympic Committee (IOC) and athletics' world governing body, the IAAF, were apparently set on a collision course over the Dwain Chambers case yesterday when IOC president Jacques Rogge advised him to "plea bargain" and trade information about the tetrahydrogestrinone (THG) phenomenon in the hope of a reduced ban for his positive test to the designer steroid.

Britain's 100-metre European champion is currently waiting to appear before an independent UK Athletics disciplinary committee and has denied taking any banned substance, but under IAAF rules is set to face a mandatory minimum two-year ban from athletics.

While the IAAF does have a rule allowing reduced sanctions for athletes offering "substantial assistance" in a doping inquiry, Arne Ljungqvist, the chairman of its medical commission, has seemingly gone out of his way to quash any such hope.

But speaking in Athens yesterday, Rogge said: "We would hope that Dwain Chambers would be wise enough to come forward to give information and in reward he would get a reduction of his penalty.

"That's a plea bargain that has been offered."

However, the IAAF rule allows that only in "truly exceptional circumstances", and this month its general secretary, Istvan Gyulai, pointed that, of the 18 athletes in four years who had applied for reinstatement or shortened bans for "exceptional circumstances", only two cases were allowed.

The hard-line Ljungqvist has suggested there would be few favours shown to any athlete looking for a reduced sentence having been caught out by the newly devised testing procedures for THG, which had previously been undetectable.

Pointedly, at the IAAF council meeting in Berlin last weekend, the Swede said: "If an athlete revealed an ongoing conspiracy against our sport it would be different.

"If an athlete found doping had come up and said, 'Look here, there is something going on', then it would probably have been favourably looked at. Just an admission by an athlete, and possibly telling how he got it and from where, would not be sufficient at all."

Meanwhile, the IAAF and UK Athletics have refused to comment on claims that Chambers tested positive for THG at the August world championships.

The IAAF confirmed that two athletes tested positive for the banned substance after retests were ordered on all 402 samples taken during the event. They have informed the separate governing bodies involved of the results but have refused to reveal any names to the public.

IAAF media director Nick Davies said: "At this point I cannot confirm it is Dwain Chambers. Any announcement must come from UK Athletics."

A spokeswoman for UK Athletics said: "We cannot confirm the results of any drugs tests under our confidentiality rules. We can only comment after the B test or if the athlete himself reveals he has tested positive."

While all this has been going on, 25-year-old Chambers has consistently protested his innocence and strenuously denies taking any banned substance.

His lawyer, Graham Shear, refused to comment on Rogge's statement yesterday afternoon and it appears he is still proceeding with efforts to clear his client's name.

Chambers was suspended from all competition earlier this month after an out-of-competition positive test for THG conducted by the IAAF on August 1st was supported by the results of his B test.