Gai Waterhouse will appear before stewards on Monday to answer charges relating to the treatment of More Joyous before the mare's failure in the All Aged Stakes.

More Joyous ran second last in the All Aged on April 27, sparking a public tirade against Waterhouse and her bookmaker son Tom from owner John Singleton who sacked the trainer in a post-race television interview.

Singleton said he had been told Tom Waterhouse knew of a problem with the mare and that she could not win.

During a much publicised hearing, Andrew Johns said he had mis-spoken when he said his Nine Network colleague Tom Waterhouse had told him before a football match the mare was "off".

Racing NSW stewards obtained telephone records showing a series of phone calls between Johns, punter Eddie Hayson and former jockey Allan Robinson who was the source of the original call to Singleton on raceday.

Hayson said two people, one a source "connected" to the stable, had told him vets had attended the mare during the days leading up to the race.

He said he decided not to back More Joyous based on that information and not anything Johns or Robinson told him.

He has not yet however, given stewards any names and risks penalties if those names are not forthcoming.

Hayson could be warned off which means he cannot attend race meetings nor operate a betting account.

Subsequent hearings have cleared Tom Waterhouse and earned Singleton a $15,000 fine for his behaviour but some questions remain.

Gai Waterhouse has been charged with not keeping proper treatment records and not telling stewards of any condition that might affect the horse's performance.

She has pleaded not guilty to both.

During the course of the inquiry it was revealed More Joyous had received her regular dose of joint medication cartrophen plus an antibiotic on race eve after heat was noticed in her neck.

Both the stable vet and Singleton's vet passed her fit to race on the Saturday.

When reminded by Racing NSW stewards of her obligation to report any issue that might affect the performance of More Joyous, Waterhouse said there was "no issue".