A group of leading dressage riders have condemned the actions of Charlotte Dujardin - with signatories including her long-time Team GB colleague Carl Hester.
Dujardin, Britain's joint-most decorated female Olympian, pulled out of Paris 2024 on Tuesday after a video emerged of her "excessively" whipping a horse.
She has since been provisionally suspended by equestrian's governing body the FEI.
In a statement, the board members of the International Dressage Riders Club (IDRC) said they "universally condemn" the actions of Dujardin.
"The board members are resolute that equine welfare must always be placed uppermost and at all times," they said on Thursday.
"The IDRC Board supports the actions taken by the FEI, the British Equestrian Federation and British Dressage to provisionally suspend Ms Dujardin."
Hester, who will compete in his seventh Olympics next week, was one of 10 board members of the IDRC to sign the statement.
He won gold alongside Dujardin in the team dressage event at London 2012, while they claimed silver together four years later in Rio and bronze at Tokyo 2020.
Dujardin had been set to compete in both the individual dressage and team event alongside Hester and world champion Lottie Fry, on horse Imhotep.
The three-time Olympic gold medallist said she was "deeply ashamed" and that her actions were "completely out of character".
Both British Equestrian (BEF) and British Dressage (BD) have imposed a provisional suspension on Dujardin pending the outcome of the FEI investigation.
On Wednesday, Dujardin had her UK Sport funding suspended pending the investigation, while she has also been dropped as an ambassador for horse welfare charity Brooke.
Two of her sponsors, equestrian insurance company KBIS and Danish equestrian equipment company Equine LTS, have terminated their deals with her.
Ingmar de Vos, president of the FEI, said he was "very shocked and disappointed" when he saw the video of Dujardin whipping a horse's legs.
The footage shows Dujardin, 39, hitting a horse with a long equestrian whip.
Whips are used in all equestrian disciplines and when employed as a training aid should be utilised lightly to communicate with the horse.
De Vos told BBC Sport: "We have many riders, we have many athletes, many horses in our sport, so it is only a very low percentage, but every case is a case too much.
"So that is why we need to constantly educate our athletes and their entourage because what was allowed 30 years ago or accepted 30 years ago is probably not any more today."
Animal rights charity Peta has called for the removal of equestrian events from the Olympic programme.
However, De Vos believes equestrian events - eventing, dressage, show jumping - will be at the Los Angeles Games in 2028 and Brisbane in 2032.
"I'm very confident because we've been doing so much for horse welfare. We will be on the programme in Los Angeles and we will also be in Brisbane," he said.