The International Olympic Committee (IOC) says a three-person panel will have the final say on which Russian athletes can compete at the Rio Games.
Last week the IOC said individual sports' governing bodies must decide if Russian competitors are clean amid claims of state-sponsored doping.
But it now says the newly convened panel "will decide whether to accept or reject that final proposal".
More than 250 Russian athletes have so far been cleared to compete.
The three-person panel comprises Ugur Erdener, president of World Archery and head of the IOC medical and scientific commission, Claudia Bokel of the IOC athletes commission, and Spanish IOC member Juan Antonio Samaranch Jr, son of the ex-IOC president of the same name.
The World Anti-Doping Agency (Wada) had recommended all Russian athletes be banned after its independently commissioned report found evidence of a four-year "doping programme" across the "vast majority" of Olympic sports.
The IOC stopped short of applying a blanket ban in a move criticised by Wada and others, while swimmers Vladimir Morozov and Nikita Lobintsev have become the first Russian athletes to appeal against their ban to the Court of Arbitration for Sport.
The Olympics start in Rio on Friday.
IOC stands by Stepanova decision
Meanwhile, Russian whistleblower Yulia Stepanova has asked again for the IOC to reassess her exclusion from Rio.
The 800m runner's testimony helped shed light on the scale of doping in Russian sport, and she was to compete under a neutral flag in Rio.
But the IOC ruled that she should not be allowed to take part as she had previously failed a doping test.
In a letter to the IOC on Saturday, Stepanova and her husband Vitaly asked the body to "reassess the decision on Yulia".
The IOC responded by saying it had rejected any review of her case and had not discussed the matter at its executive board meeting.
"The final decision has been taken already," IOC spokesman Mark Adams said.
Credit: The BBC