The investigation by French authorities has so far seen former International Association of Athletics Federations (IAAF) president Lamine Diack arrested after allegedly protecting Russian athletes who had failed drugs tests, while a number of other officials have also been placed under arrest.
Prosecutors are now looking into the processes that saw the 2016 and 2020 Olympics awarded to Rio de Janeiro and Tokyo respectively.
The French authorities failed to provide a response when contacted by CNN to find out further details regarding the widening of the investigation.
The International Olympic Committee (IOC) has told CNN that it has been in "close contact" with French prosecutors since the probe started last year, while it has also applied to become "a party to the investigations."
The IOC adopted a new set of rules after a number of its members were accused of taking bribes from the Salt Lake City organizing committee during the bidding process for the 2002 Winter Olympics.
The bidding and voting process for the 2016 Olympics concluded in 2009, with Rio seeing off competition from Madrid, while Tokyo was awarded the 2020 Games ahead of Istanbul and Madrid in 2013.
Organizers of Tokyo 2020 told CNN that "the Games were awarded to Tokyo because the city presented the best bid."
"Tokyo 2020 considers that the allegation is beyond our understanding," Tokyo 2020 spokesperson Hikariko Ono said. "Tokyo's bid was about Japan's commitment to address issues around the integrity of sport.
"Today, Tokyo 2020 is even more committed to contributing to safeguard the place of sport in society in these fast-changing and challenging times for sport."
Rio 2016 communications director Mario Andrada, meanwhile, was reported by BBC Sport
as saying the Brazilian city "won the right to host the Games because it had the best project."
"The difference in the votes, 66 to 32 against Madrid, excludes any possibility of an election that could have been rigged," Andrada added.
French prosecutors are investigating whether Diack, who chaired the IAAF for 16 years before stepping down in August, covered up positive tests by Russians in exchange for $1.09 million from the country's athletics federation.
The 82-year-old -- who resigned as an honorary IOC member a day after being provisionally suspended by the organization following the start of the French investigation -- denied the accusations put to him by a French judge in November, prior to his release on bail.
In December, financial prosecutors in Paris filed tougher charges against Diack, accusing him of "active corruption" -- which generally involves offering something -- where he had previously been accused of "passive corruption."
Diack's son Papa Massata Diack, a former IAAF consultant, is also being investigated and a warrant for his arrest has been issued by Interpol.
Papa Massata Diack, as well as Russia's former athletics federation president Valentin Balakhnichev and Russia's ex-chief coach for long-distance athletes Alexei Melnikov, were all banned for life by the IAAF over corruption charges last month.
The trio were alleged to have blackmailed Russian distance runner Lilya Shobukhova into paying them off to keep results of her positive drug tests secret.
Russia was provisionally suspended
as an IAAF member in November following a damning report by the former head of the World Anti-Doping Agency
that claimed the country had engaged in widespread and state-sponsored doping.