The International Olympic Committee (IOC) will not test athletes for EPO and human growth hormone until it has a system which is 100 per cent reliable, senior IOC member Jacques Rogge said yesterday.

Rogge, who is the chairman of the IOC co-ordination commission which is in Sydney to inspect preparations for the 2000 Olympic Games, said it was unrealistic to expect that elite sport would ever be drug-free.

"The IOC has funded research into the detection of erythropoietin (EPO) and human growth hormone, which are probably the two most widely abused drugs that we cannot trace today. Whether this will be achieved by 2000 I dearly hope, but no one can assure that," said Rogge.

EPO is a naturally occurring substance, which lifts the number of red blood cells and cannot be detected by urine testing. It increases endurance but lifts the risk of heart failure.

"We are progressing, it is very difficult research because the two drugs are produced by the human body so it is very difficult to make a differentiation between . . . what you take in and what your body produces.

"We know that some day we will succeed . . . hopefully before Sydney. If the method is found it will be implemented at Sydney. The problem is . . . we have a method to have 80 per cent certainty, but 80 per cent certainty is not enough to face a court.

"You need 100 per cent certainty and we are trying to close the gap of the last 20 per cent which is extremely difficult."

Rogge said it was the IOC's moral and ethical responsibility to limit doping in sport to the lowest possible level.

"But it is like criminality in a society, there is no crime-free society, there will always be cheaters, there will always be scientists who will have a small lead, or sometimes a big lead on the research we are doing."

Rogge said the IOC was ready to implement blood testing to supplement urine testing at the Olympic Games if and when it was required.