The jockeys, secretly recorded by detectives, were heard providing the drug suspect, who has since been jailed and is facing serious drug charges, with inside information on racing. The man has a reputation as one of Australia's biggest punters.
Racing Victoria stewards have launched an inquiry into the relationship between the suspect and at least seven jockeys and trainers.
Australian newspaper The Age said the drug suspect once headed a betting syndicate which hit bookies with a series of coordinated plunges based on inside information. It said he was alleged to control the notorious 'tracksuit gang', a group of punters who placed massive bets on horses at tracks on the east coast.
The man, a millionaire, is banned from owning racehorses in Victoria.
It is believed at least three jockeys, all considered among the best in Australia, were recorded when the man's phones were tapped as part of a long-running investigation.
Racing Victoria chief steward Des Gleeson said: "We have interviewed a number of licensed persons, some on more than one occasion, because of information we have received into their possible relationship with this man. But we can't take it any further at this stage."
While police sources said there was no suggestion the jockeys were rigging races, the inside information could prove embarrassing. It is not known if the jockeys were paid for the information.
Gleeson, said it was an offence for a jockey to place a bet, have an interest in any bet or to accept money for rides other than from owners and trainers.
