The successful, tragic and sometimes turbulent career of champion jockey Damien Oliver may be over following his admission to one of the most serious charges in racing.

Oliver admitted on Monday to placing a $10,000 bet on a rival horse in a race in which he was riding at Moonee Valley in October 2010.

He also admitted to using a mobile phone from the jockeys' room to place the bet.

The charges come at a time when racing in Victoria is reeling from allegations of race-fixing and widespread doping of horses.

The sport is also dealing with threats made by a leading jockey against the chief steward and a spate of incidents of trainers flaunting the rules by administering treatments to horses on race days.

Based on recent precedents, Oliver, 40, is facing at least a 12-month ban, a period which would make it difficult for him to resume riding at any meaningful level.

For the jockey who has won two Melbourne Cups and about whom a movie was made two years ago, the fall from grace is another tragedy in a life containing a big share of them.

His father Ray Oliver, also a jockey, died in a race fall at Kalgoorlie when his youngest son was three years-old.

But it was the death of his older brother Jason in a fall during a trial at Belong in Perth in 2002 and his ride to win the Melbourne Cup the day after the funeral that made Oliver a household name and inspired a movie.

Since then, he has been involved in other police investigations, notably in September 2010 concerning non-racing matters. No charges were laid against him.

Oliver's formal admissions concerning the charges he now faces came on Monday, two days after the biggest racing carnival in Australia ended and after weeks of speculation and debate on whether he should be riding while under investigation over the bet.

Both charges revolve around a $10,000 bet Oliver admits to having placed on the horse Miss Octopussy, who started favourite and won at Moonee Valley in October 2010 and paid a return of $2.30.

Oliver rode the second favourite Europe Point in the race. There are no charges relating to his handling of that horse.

The second charge of using a mobile phone is in direct contravention of the rules of racing which prohibit jockeys even having a phone in their possession in the vicinity of the jockeys' room.

Oliver has been one of the most successful jockeys in Australia for two decades and has won seven Melbourne jockeys' championships.

He has ridden two Melbourne Cup winners, four Caulfield Cup winners and twice has won the Cox Plate.

He has been associated with some of the most outstanding horses of modern times, including the champion sprinter Alinghi, which he rode to victory at Royal Ascot, Dane Ripper, on which he won the Cox Plate, and Northerly, which won the same race twice.

When the allegations he has now admitted to emerged, Oliver was sacked from his rides in the Caulfield Cup and Cox Plate, but still rode three group one winners during the spring carnival, the latest of them Happy Trails, which won Saturday's Emirates Stakes.

The hearing of the two charges against him is scheduled for next Tuesday.