Racing Victoria chief executive Rob Hines said various investigations were under way, instigated by a team that monitors betting patterns on most of the 4000 races run in Victoria every year. 

``There are a number of ongoing investigations,'' Hines said. 

``Some of those may lead to inquiries and charges.''

Racing Victoria stewards laid long-anticipated charges against Oliver yesterday, some three weeks after it emerged he was under investigation for placing a $10,000 bet on a rival  ?horse and rider at a Moonee Valley meeting in 2010. 

The charges followed a written admission to a charge of betting on the horse Miss Octopussy, the favourite and winner of a race in which Oliver rode the second favourite, and to another charge of using a mobile phone while in the jockeys' room to place the bet through a third party. 

The admission was tendered by Oliver to Racing Victoria on Monday. 

The Oliver case ranks among the most scandalous in the sport in decades, not because of the sinister nature of the charge, but because it involves one of the world's greatest jockeys. 

Oliver is one of the highest-profile jockeys in Australia, mostly for the right reasons. 

 ?The 40-year-old has won seven Melbourne jockeys' premierships, two Melbourne Cups, four Caulfield Cups, two Cox Plates and a Golden Slipper. 

Oliver's betting breach generated a string of mostly unfounded revelations, including one that he had made official admissions relating to the current charges a week ago. 

The reports prompted criticism of Racing Victoria for not standing him down pending the result of a hearing and suggestions the organisation wasn't doing enough to safeguard the integrity of one of the state's biggest industries.

The charges against Oliver will be heard on Tuesday.