Australian equestrian star Shane Rose’s chances of attending a fourth Olympic Games have been thrown into doubt after the three-time medallist was stood down by Equestrian Australia for wearing a skimpy “mankini” costume during a fancy dress class at an event last weekend.

The light-hearted event sees riders dress up in costumes as they compete, and Rose wore three different costumes on the day: a gorilla suit, a Duffman beer suit and a mankini, the G-string swimsuit made famous by the character Borat.

The sight of Rose wearing a mankini going over jumps in front of a crowd where children were present was enough to prompt a complaint to Equestrian Australia and Sports Integrity Australia. EA chief executive Darren Gocher said the complaint prompted an internal disciplinary process.

That review will determine if Rose’s mankini display will earn him a sanction, ranging from a warning through to a fine and/or suspension.