Leading trainer Leon Corstens says Damien Oliver will be "busting his boiler" to win on the $500,000 Thousand Guineas second favourite Commanding Jewel at Caulfield on Wednesday.

Oliver has been dumped from two major rides in the wake of allegations he bet on a rival horse in a race in 2010, but Corstens said he never had any thoughts of replacing him.

In fact, according to Corstens, Oliver will be out to do his utmost to secure victory in the Group One 1600m race.

"He knows the filly very, very well and I think he's ridden under more adverse conditions than this," Corstens said."

"I never had second thoughts. Even if the owners hadn't agreed I would have still advised them to leave him on."

Oliver took Media Puzzle to victory in the 2002 Melbourne Cup just a week after his brother, Jason, was killed in a barrier trial fall in Perth.

"I think I'm getting him at the right time," Corstens said. "I reckon he'll be busting his boiler to try and win for us."

Prominent owner Lloyd Williams has taken Oliver off his Cox Plate contender Green Moon while he has also lost his ride on the Luca Cumani-trained My Quest For Peace in Saturday's Caulfield Cup.

Oliver allegedly bet $10,000 bet on a horse called Miss Octopussy, who won at Moonee Valley in 2010. He was riding the second favourite in the race, Europa Point.

Corstens said he had no need to call Oliver and confirm with him he still had the Commanding Jewel mount.

"I didn't have to do that, it never entered my head," he said. "He's D. Oliver and he's ridden plenty of Group One winners.

"I don't think I could have anyone any better.

"His rides on her have been the best you could possibly do so, full steam ahead."

Oliver rode trackwork at Flemington on Tuesday morning for a number of trainers, including Clinton McDonald, Mick Price and Robert Smerdon.

Corstens said Commanding Jewel would go into tomorrow's feature race in better shape than she was when she finished third in the Edward Manifold Stakes.

"I'm rapt in her, I think she's improved since the run the other day," he said.

"I've got to be honest, I'd like to see a little bit of rain. I just reckon she might be a better horse with the sting out of the ground."

Rain was forecast for late on Tuesday evening, clearing on Wednesday morning.