Up to 10 jockeys face bans because they placed bets through third parties, News Limited newspapers say.
It is believed betting by jockeys, brought to the surface with leading rider Damien Oliver admitting to betting $10,000 on a horse running in the same race in which he was riding, is widespread.
News Limited says one punter is believed to have co-operated with authorities only after being threatened with a lengthy ban from race tracks.
"Well-placed sources say he maintains a ledger that records bets of a number of top-flight jockeys," reports said on Thursday.
"Industry sources say as many as 10 high-profile jockeys could face sanctions as a result of inquiries under way, further damaging a sport still reeling over the Oliver affair."