The IOC has so far retested more than 1,000 samples from the London and Beijing Olympics, aiming to detect performance-enhancing drugs that were not identifiable four and eight years ago.
IOC braced for 'many more' cases of London doping
Retesting of samples from the London 2012 Games is expected to reveal "many more" cases of doping, a senior International Olympic Committee official warned on Wednesday.
Dozens of competitors have been caught doping, among them Olympic champions and other medallists, as the IOC attempts to clean up Olympic competition after one of the worst crises in its history.
"There will be many more (cases) to come (from London) in the coming weeks and months," warned Richard Budgett, IOC medical director.
"We are still getting positive samples from London, I expect this will continue," he told reporters in Lausanne, where the IOC is based.
More than 100 new positive test results have been unearthed by the IOC's reanalysis, it says.
Prime among the countries snared is Russia, whose athletes were banned from the Rio Olympics this summer because of state-sponsored doping.
The IOC initiated the retesting programme last year using improved techniques to catch doping cheats.