Australian Olympic shooting gold medallist Russell Mark is set to parade in a lime-green "mankini" made famous by the movie character "Borat" at the opening ceremony of the London Olympics as the penalty for losing a bet.

Mark, who won double trap gold at the 1996 Atlanta Games and silver in Sydney, pledged to wear the skimpy swimsuit worn by British comedian Sacha Baron Cohen in the 2006 film if Melbourne-based Carlton lost to St. Kilda in the Australian Football League.

Carlton suffered a shock four-goal defeat in the match on Monday night and Mark owned up to making the bet on local radio.

"Oh, I must've been intoxicated. Carlton promise so much and just deliver so little. It kills me," the burly 48-year-old said on Tuesday.

"Anyway, a lot of people would think a mankini might look better than the uniform they've nominated for us, so I don't know if it's such a bad thing."

The one-piece swimsuit would certainly stand out among the other Australian athletes, who will be kitted out in stodgy green blazers and white slacks which fashion critics have generously described as "retro".

An Australian Olympic Committee spokesman recommended Mark keep the mankini in the closet.

"Age is the problem here. Russell is no spring chicken, his days of being a model are long gone, and we don't think it would be a good look for the team to have Russell in a mankini," the spokesman told local media.

"Besides, this will be his sixth Olympics and he is a chance to be named as flag bearer. Imagine the flag bearer out in front of our team in a mankini. And a big, butch shooter at that.

"As we all know the London weather is fickle and we would not want him to catch cold."