LIMA - Lawyers for the International Olympic Committee on Monday contacted Brazilian judicial authorities to request any evidence regarding the involvement of Rio de Janeiro Olympics chief Carlos Nuzman in alleged corruption, IOC chief Thomas Bach said.

Brazilian investigators said last week Nuzman, the head of the national Olympic committee and subsequent Rio Games chief, had arranged a $2 million bribe to bring the 2016 Games to Rio, despite the city having the worst conditions to host the event.

Police in Rio raided Nuzman's house after prosecutors accused him of conspiring with former state governor Sergio Cabral, already convicted in a separate corruption case, to buy the Games.

"Since this morning our lawyers have been in contact with Brazilian judicial authorities," Bach said in Lima, Peru. "Once evidence is provided, we will act."

The legacy of South America's first Olympics, which ended just over a year ago, has been muddied by allegations of graft.

Nearly every infrastructure project connected to the Games is under investigation and prosecutors allege major construction firms bribed politicians and others to win contracts worth billions of dollars for the event.

The alleged votes-for-cash affair was triggered by an ongoing French investigation, with former international athletics chief Lamine Diack and his son, Papa Massata Diack, seen as leading figures in the affair.

Diack, a former IOC member, has already been stripped of his honorary IOC membership.

In a statement earlier on Monday the IOC repeated claims from French prosecutors investigating the affair that Diack was under suspicion of having run a votes-for cash scheme "over the designation of host cities for the biggest global sporting events."

Both Diack and his son have rejected the allegations.

Massata Diack told Reuters last week the claims were "the biggest lie in the history of world sport."

Bach said there was "no collective responsibility" for the IOC and the Olympic body would act, as it had in the Diack case, once it had evidence.

"It was a couple of days after evidence was provided against Diack that the IOC executive board took action and he lost his IOC honorary position (in 2015)," Bach said

"There are allegations concerning Mr Nuzman. He is not even charged so far. This needs to be clarified and then action will be taken.

"Once evidence is there then we will act and the (IOC) ethics commission will be in a position to make recommendations in this respect."

Reuters