Retired jockey Allan Robinson says he is horrified by the public falling out of John Singleton and trainer Gai Waterhouse that followed a phone call he made to the millionaire businessman over the condition of his horse More Joyous.

Singleton has accused Waterhouse's son, the bookmaker Tom Waterhouse, of telling people the champion mare could not win the All Aged Stakes at Randwick last Saturday.

He has since withdrawn his stable of horses from Gai Waterhouse.

"I'm horrified," Robinson told Today Tonight on the Seven Network, referring to the fallout following the race when More Joyous finished seventh in a field of eight.

He defended Gai Waterhouse saying she would not let a horse run if it was not 100 per cent, but then pointed out that something must have been wrong, because More Joyous finished seventh.

When asked if he would do the same thing again, Robinson made a lengthy pause, before saying: "Should you let it lie? Don't know."

At a trackside inquiry on Saturday, Singleton refused to divulge the names of "trusted friends" who had told him Tom Waterhouse was saying there was a problem with More Joyous.

On Tuesday Singleton's friend and rugby league legend Andrew Johns released a statement dismissing claims Tom Waterhouse had tipped him off about the condition of More Joyous.

But on Wednesday night, Singleton broke his silence.

"Names have already been named so my reluctance to name names has been taken away by the names naming themselves," he told the Nine Network.

When asked if Johns and Robinson were those people, Singleton replied: "Yeah, they're both the people who rang me, yes."

Tom Waterhouse has denied the accusations and will front the reconvened inquiry next Monday.

It was revealed during Saturday's preliminary inquiry that More Joyous had been treated with antibiotics leading up to the All Aged but she had been cleared to run by two vets, including the one employed by Singleton.