Kermond has been booted from Australia's Olympic team after testing positive for a metabolite of cocaine on June 26.

The three-time Australian equestrian champion hopes one day to be forgiven.

"It is likely that the positive result was from a single recreational use of the drug at a social event and had no connection with my sport of equestrian," Kermond said in a statement.

"I am extremely upset and remorseful as to what has happened and I accept full responsibility.

"I am truly sorry as I have let a lot of people down including my family and teammates.

"Hopefully one day I can be forgiven for my mistake (and make) amends through better actions and continued contribution to the sport I know and love."

Kermond's A sample in a test conducted by Sport Integrity Australia was positive and he was suspended by Equestrian Australia (EA).

"Kermond is prohibited from participating in any WADA compliant event, including the Tokyo 2020 Olympic Games, while the provisional suspension is in place," an EA statement on Wednesday read.

Under Australia's anti-doping policy, Kermond can have his B sample analysed.

"Equestrian Australia has spoken with Mr Kermond and support services will be offered to him," EA said.

The 36-year-old from Victoria was to have made his Olympic debut in Tokyo, among three showjumpers on a nine-strong Australian equestrian team.

His suspension is a blow to the Australian Olympic Committee (AOC) just two days out from the opening ceremony.

"The Australian Olympic team selection committee will consider the matter later today," an AOC statement read.

Kermond's selection for the Olympics attracted scrutiny.

He's ranked 1013th on world standings but has links to one of two national selectors, Stephen Lamb.

Lamb is employed as marketing manager at a horse nutrition company which sponsor's Kermond's Yandoo Park, which offers agistment and training.

Selectors overlooked Rowan Willis, Australia's top-ranked rider at 59 in the world, and Lamb has said he stepped aside when Kermond's selection was discussed.

Equestrian Australia (EA) in June last year entered voluntary administration, with control of the elite program handed to the Australian Institute of Sport (AIS).

In May this year, EA wrote to the AIS to confirm proper governance practices were being followed in selecting the equestrian team for Tokyo, according to News Corp reports.

Australian Associated Press