The International Olympic Committee (IOC) and the World Anti-Doping Agency (WADA) will re-analyse selected samples from the past two Olympic Games in a bid to uncover undetected doping violations.
The re-testing of hundreds of samples from Beijing 2008 and London 2012 is already under way and is focused on athletes expected to compete in Rio this year.
New methods of analysis that were not initially available during testing at the previous two Games will now be used in attempt to "protect clean athletes".
During the WADA Symposium in Lausanne, IOC Medical and Scientific Director Richard Budgett said: "The aim of the programme is to prevent athletes who cheated in London or Beijing, and got away with it because we didn't have as advanced methods of analysis as we do now, from competing in Rio de Janeiro.
"The results will come in a number of weeks or months.
"We are trying passionately to protect those clean athletes who are going to Rio 2016. And the best way to do that is to catch the cheats and deter the cheats before we get to Rio de Janeiro.
"So that's why we launched this initiative with the task force even before the Olympic Games open."
Russia's track and field athletes were banned from international competition by the IAAF last November following allegations of state-sponsored doping in a report from an independent commission established by WADA.
WADA has also set up a task force aimed at gathering intelligence and co-ordinating any additional testing required ahead of the Games.