Increased dope testing allied to earlier pre-Olympic Games tests is having a deterrent effect on potential cheats, International Olympic Committee President Jacques Rogge says.
The 65-year-old Belgian had predicted on the eve of the Games that he expected there to be between 30-40 positive tests, extrapolated from previous Games and the fact that there would be many more tests than before.
Thus far there have been five such cases although Greece's 2004 Olympic 400 metres hurdler Fani Halkia was tested at a pre-Games training camp with the latest being a positive A sample for Ukraine's heptathlon silver medallist Lyudmila Blonska.
Mr Rogge, though, said he could see discernible progress being made against doping.
''I am a very modest man, but we are making progress in the fight against doping in sport,'' he said.
''There were 12 positive tests in Sydney and 26 in Athens and one could say at the same time that if we do not reach that number [his estimate of positive tests here] then the deterrent factor is working.
''If there are more tests then athletes get scared about resorting to doping.''
But Australian Olympic Committee chief John Coates says the extraordinarily low number of positive drug tests at Beijing could be because athletes have found new ways of avoiding detection.
Mr Coates says athletes may have been scared by the Beijing organisers' threats to crack down hard on drugs, or they may simply have found better ways to cheat.
''They've certainly trumpeted that they were going to be, and there have been, 4500 tests double the number we had in Sydney,'' he said.
''They've trumpeted that they were better able to identify human growth hormone.
''So I don't know whether it's because of the deterrent effect of all of that or because the athletes have been able still to find a way around it.''
Mr Rogge said one of the improvements that had been made since Athens was that federations had taken on board advice from the IOC about dope testing.
''Prior to the Athens Games there were 26 positive tests discovered by international federations, especially in weightlifting.
''We said to the federations that they should begin their pre-Games testing earlier for these Olympics.
''Thus in the six weeks leading-up to the Games there were 39 athletes who tested positive, in particular the Greeks and the Russians.
Mr Rogge said even those athletes who perhaps had got hold of so-called designer drugs which are at present undetectable could not be sure of getting away with it in the long term as there was no statute of limitations on drugs cheats.
''That is the reason why we freeze the samples,'' he said. ''They can be opened up at any time once we have the knowledge of how to detect a drug and then test for it.''
''This too has had a deterrent effect.'' AFP/AAP