John Singleton can be compelled to name names when he appears at a reconvened stewards inquiry into his allegations bookmaker Tom Waterhouse knew More Joyous could not win Saturday's All Aged Stakes.

At the initial inquiry, the high-profile businessman refused to divulge the names of "trusted friends" who had told him Waterhouse was saying before the race there was a problem with the Singleton-owned mare trained by the bookie's mother Gai.

Tom Waterhouse has denied Singleton's public claims and says he backed More Joyous, who finished second last, and that the win by All Too Hard was a $300,000-plus worse result for him.

Singleton made the accusations in pre and post-race interviews and announced after the race his 35-year association with the trainer was over.

Racing NSW chief steward Ray Murrihy said as a registered owner Singleton would be asked to name the people who gave him the information at Friday's inquiry if it was deemed relevant.

"If we think it is pertinent to the inquiry, John Singleton will be asked to tell us who these people were," Murrihy said.

"Tom Waterhouse will also be asked to come to the inquiry."

"We will examine all betting records on the race before then.

At Saturday's inquiry, Gai Waterhouse said the mare had been treated with antibiotics on Thursday for heat in her neck, something she and her vet Leanne Begg considered minor.

More Joyous was examined by Begg and Singleton's vet on Saturday morning and both agreed she was fit to race.

Stewards have collected treatment records from the Waterhouse stable.

Singleton told the inquiry he would only reveal the names of those who told him there was a problem with the mare if he was legally obliged to do so.

Murrihy responded by saying his panel needed to establish if there was any substance to the allegations made.

"We cannot put much weight on racecourse tattle," he said.

"Millions of dollars are being invested on the race and we need to get to the bottom of this and find out if Tom Waterhouse is being misrepresented in this."

Among the people Singleton refused to name was one he said was a retired Group One winning jockey.

Retired NRL star Andrew Johns has denied reports in Fairfax Media he was one of the people involved.

Singleton removed seven horses from the Waterhouse stable on Sunday and said he would announce new trainers in the coming weeks.