LONDON -- Armed with more effective methods and targeting specific athletes, the IOC plans to retest hundreds of doping samples from the 2008 Beijing Olympics in a bid to catch any drug cheats who escaped detection at the time.

IOC medical director Richard Budgett said Wednesday that some retests have already been carried out on stored samples from Beijing, the 2010 Winter Games in Vancouver and the 2012 London Olympics.

Retesting opens the possibility of athletes being stripped of Olympic medals up to 10 years after they won them.

"Even if it's five or 10 years later, it's really an important thing to do," Budgett said. "It's not ideal. You want to do it as close as possible to the time, but if you've got no option but to do it later, then that's what you have to do."

The International Olympic Committee has stored Olympic doping samples since 2004 at a lab in Lausanne, Switzerland, keeping them for reanalysis when new methods become available. The original eight-year statute of limitations has been extended to 10 years under the new World Anti-Doping Code, meaning the IOC can retest Beijing samples up to 2018.

A small number of Beijing's total of 4,000 samples have already been retested based on intelligence about suspected cheaters, with no positive tests confirmed so far, Budgett said.

While an official decision hasn't yet been made by the IOC executive board, Budgett said a "significant number" of samples will be reanalyzed in the coming months from athletes who could compete in next year's Olympics in Rio de Janeiro.

"Another significant number will be done before the samples expire in 2018," Budgett said on the sidelines of the Tackling Doping in Sport conference at the Emirates Stadium in London. "It will be in the hundreds. Who knows what tests are going to be developed over the next two years? It makes a lot of sense to wait another couple of years for the majority."

Retests will also be targeted based on intelligence from recent positive cases and allegations of widespread doping in Russia and Kenya.

"We will document that sort of intelligence," Budgett said. "The countries where doping is prevalent and particularly where we know now that doping was prevalent, say back in 2008, that will be taken into account."

A few target tests have been done so far on Vancouver and London samples, Budgett said, adding he had no positive findings to report.

It's not the first time the IOC is going after doping cheats from Beijing. It retested some samples a year after the 2008 Games in search of the blood-booster CERA and caught five athletes -- including Bahrain runner Rashid Ramzi, who was stripped of his gold medal in the 1,500 metres.

Retests of samples in 2012 from the 2004 Athens Olympics led to five athletes being stripped of medals for using steroids, including men's shot put winner Yuriy Bilonog of Ukraine.

In 2013, the IOC retested about 350 samples from the 2006 Winter Games in Turin, Italy. Budgett said the results of those tests remain confidential for legal reasons. At least one positive case is believed to remain under review.

Budgett said the Beijing retests will use the "long-term metabolite" method that can detect the use of steroids going back several months -- rather than days -- and an improved analysis that is more sensitive in detecting the endurance-boosting drug EPO.

"You can look back at something that you couldn't report as positive in the past and say, under the new rules, we can report that as positive," Budgett said.

On a separate issue, Budgett said he is confident the anti-doping lab in Rio will be reinstated by the World Anti-Doping Agency in May and be ready for use at next year's Olympics. The lab was suspended by WADA in 2013 for repeated errors, forcing FIFA to send samples to Switzerland for testing during last year's World Cup.

Budgett said the IOC plans to conduct "roughly the same number" of tests in Rio as the 5,000 it carried out in London. Rather than increasing the number of tests as the IOC usually does at each games, Budgett said "we want to move away from a total focus on numbers" and concentrate on intelligent, targeted and flexible testing.

Also Wednesday, WADA and the IOC said world governments have pledged $6.45 million toward anti-doping research, bringing to nearly $13 million the total fund for finding new tests. The funds are split 50-50 between the IOC and governments.

"We must consider every cent in the fight against doping as an investment in the future of Olympic sport, not as an expense," IOC President Thomas Bach said.