Marc Hodler, a senior member of the IOC, alleged malpractice in the voting for the 1996 Atlanta Games, the 2000 Sydney Olympics and the 2002 Salt Lake Games.
He said a group of four agents, including one IOC member, have been involved in promising votes for payment, but declined to identify them.
"The four agents try to make a living out of this," he said. "I missed a chance to be a rich man. Some of the agents ... say, 'I can offer this or that number of votes.' The price would be between $500,000 and $1m for a number of votes, a bloc."
The agents, he added, then charge the city winning the bid "something like $3m to $5m".
Mr Hodler, an 80-year-old Swiss lawyer, said there was one agent who boasted "that no city has ever won the Olympic Games without his help", although "no one can prove that".
Bruce Baird, the former New South Wales minister in charge of Sydney's 2000 Olympic bid, has also revealed he was asked to offer bribes in exchange for votes. He said he refused.Reuse content