Olympics chiefs have insisted that a number of high-profile doping scandals have not tarnished the Athens Games.
Two Olympic champions have been stripped of their medals and seven athletes have failed doping tests.
Three other competitors, including Greek sprinter Kostas Kenteris, dropped out following doping test violations.
"We should keep things in perspective. There are 10,500 athletes and there have been some wonderful successes," said IOC spokeswoman Giselle Davies.
"We so far have seven positive doping tests and three doping violations and in Sydney we had 11."
Davies also revealed that a 25% rise in testing from Sydney to Athens was likely to result in more cases.
"The IOC would not be surprised if more violations of doping
rules were found," she said.
Hungarian Olympic discus champion Robert Fazekas was the second athletics gold medallist to forfeit his title for "refusing or failing to admit a urine sample" on Tuesday.
Fazekas was target-tested after the IOC received information on the Olympian.
"We already had some details on the Hungarian discus thrower, so what
happened was no surprise," said IOC medical commission chairman Arne Ljungqvist.
"What he did was almost stupid. But it does highlight the efficiency of the
testers and, more importantly, shows that in 2004, at the highest level of
competition, with the most sophisticated athletes, coaches and advisors, we are
still finding people using the same banned substances as they did 20 years ago.
Ljungqvist insisted that the IOC were within their rights to employ such tactics.
"Of course we actively target test," said Ljungqvist.
"Why shouldn't we. We can identify risk groups through experience, we get
information through active research and we are also assisted by others.
"We are not saying any athlete who performs well is going to be suspected,
that would be disastrous. But it would be irresponsible not to act on the
information we receive."
On Sunday, Irina Korzhanenko of Russia was stripped of her women's
Olympic shot put gold after testing positive for a
So far 2,015 of the expected 3,000 IOC-run drug tests have
"The IOC is determined in its fight against doping. This
fight...is a priority," Davies said.
Before the Games even began, Greek sprinters Kenteris and Katerina Thanou dropped out after missing a dope test.
But Games officials insisted that a high number of positive cases meant the anti-doping programme was working.
"The more athletes that are caught cheating in our Games the
cleaner athletics we will have," Games spokesman Michael