After first accusing De Boinville of being “abusive”, Queally told The Racing Post, external on Wednesday he had received “repeated racist abuse” from his rival.
The Irishman, riding I’ll Sort That, and De Boinville on Act Of Innocence could be seen exchanging words at the start line, but the Englishman denies any wrongdoing.
De Boinville told BBC Radio 5 Sports Extra on Thursday: “It is an ongoing investigation.
“The stewards are gathering all the evidence they can from all the video footage.
“From my point of view, I deny all the allegations against me.
“I can categorically say there weren’t any racial slurs or anything like that. Let’s let it play out.”
Queally, 37, appeared to topple off his horse before Wednesday’s race started and had to be checked over by a doctor. He was given the all-clear to race, along with Ballyfad, who was kicked pre-race and assessed by a vet in a chaotic few minutes.
A number of false starts to the planned rolling start meant the horses were moved to a standing start at the tape – leaving jockeys jostling for position.
After the race, Queally, who finished fifth, was interviewed by ITV Racing before entering the weight room.
He said: “Being abused by an English rider, Nico de Boinville, not very nice.
“I am an amateur, coming over here and riding in front of my kids. Horrific.”
When informed of Queally’s comments about a difficult start to the race, De Boinville responded: “Maybe he should look in the mirror.”
Legendary jockey AP McCoy said Queally has “as much right to be there as anyone”, while Ruby Walsh said the start system “hasn’t worked for 20 years”.
Walsh told ITV: “It’s 2026. How has nobody devised a tape that rolls in front of the horses?
“The tape should have been in front of them when they went on to the track and it should be moved in front of the horses.
“We can send missiles after fighter planes in the Gulf, but nobody can design a rolling flyaway tape. That’s the joke.”