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.
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.

The draft legislation seeks to protect sensitive personal data from hacking and government surveillance.
EU citizens are entitled to personal privacy and this extends to online communications, the committee argues.
A ban on "backdoors" into encrypted messaging apps like WhatsApp and Telegram is also being considered.
Encryption involves digitally scrambling a communication to protect its contents, and then using a digital key to reassemble the data.
End-to-end encryption means the company providing the service does not have access to the key, meaning it cannot "listen in" to what is being shared - giving the sender and recipient added confidence in the privacy of their conversation.
"The principle of confidentiality should apply to current and future means of communication, including calls, internet access, instant messaging applications, email, internet phone calls and personal messaging provided through social media," said a draft proposal from the European Parliament's Committee on Civil Liberties, Justice, and Home Affairs.
The proposal seeks to amend Article Seven of the EU's Charter of Fundamental Rights to add online privacy and will require approval by the European Parliament and the European Council before it can be passed into law.
During the UK's recent election campaign, the Conservative Party said that tech firms should provide the authorities "access to information as required" to help combat online radicalisation, but ministers have also said they do not want to weaken encryption.
That has led to some confusion among tech industry leaders as to whether the government wants some kind of "backdoor", a way to have end-to-end encryption disabled in specific cases, or some other action.
However, cyber-security experts warn that criminals can still find a way to protect their communications, even if end-to-end encryption is banned.
"There are lots of existing techniques law enforcement can use," Dr Steven Murdoch, a cyber-security researcher in the department of computer science at University College London told the BBC News website.
"One of them is traffic analysis, which is looking at patterns of communications, eg who is talking to who, when and from what location.
"The other one is hacking - equipment interference in British law - which can happen before data is encrypted and after it's been decrypted, so there are still ways for law enforcement to gain access to information."
In the Manchester, Westminster and London Bridge terror attacks, the perpetrators were already known to UK security services, Mr Murdoch added.
"They were not stopped because there were either insufficient resources or the resources were not sufficiently prioritised," he said.
"The suggestions being considered by the UK government would be worse for computer security. So much of people's lives are now carried out online. We should have privacy online just as we have offline."
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.
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A European Parliament committee wants end-to-end encryption to be enforced on all forms of digital communication to protect European Union (EU) citizens.