Australia's leading jockey Damien Oliver, riding one of the favourites in Tuesday's Melbourne Cup, has admitted to racing authorities that he bet on a rival horse in 2010, a report said.
The two-time Melbourne Cup winner, who will ride French-trained equal favourite Americain in the $6.2-million (U.S.) race at Flemington, wagered $10,000 (Aus.) and expected to be charged soon, Fairfax Media said.
Fairfax said sources close to the jockey confirmed he admitted last month to breaching the rules of racing by betting on rival horse Miss Octopussy, which won the race at Melbourne's Moonee Valley.
Oliver, competing in the same race, finished sixth.
Newspaper reports alleged Oliver told his supporters he expected to be suspended for between nine and 12 months but that he may retire in a move that could see him avoid a public hearing or a penalty from Racing Victoria.
Jockeys are forbidden from betting on any horse, while betting on a horse in the same race is one of the "gravest breaches" of Australian racing laws.
Publicly, Oliver has refused to deny placing the bet, Fairfax Media said, adding that his admission raises serious questions about why he has been allowed to continue riding, and why he has not been charged by stewards.
Fairfax said Racing Victoria chief executive Rob Hines declined to respond to its specific questions about the affair, other than to say an inquiry "is expected to be finalized in the next week or so".
Oliver stands to earn hundreds of thousands of dollars if he rides Americain to victory in Tuesday's Melbourne Cup, following his ride on Saturday's Victoria Derby winner, Fiveandahalfstar, which earned him $45,000 (Aus.).