The Olympic hopes of Nick D'Arcy, Australian butterfly swimmer, may be dashed after he was charged with assault occasioning grievous bodily harm. Police allege that D'Arcy was involved in a fight with Commonwealth champion Simon Cowley outside a Sydney bar last weekend.

The Australian Olympic Committee (AOC) and Swimming Australia say they will jointly investigate the incident before deciding whether D'Arcy can go to Beijing.

Swimming Australia's chief executive, Glenn Tasker, told ABC in Australia: 'Given the nature of the charges and the time frame that it will take for the legal process to happen, I wouldn't want to pre-empt the Australian Olympic Committee and their decision, but certainly his position at this point is in some doubt. The AOC is developing a series of questions that they would like to put to Nick D'Arcy and those questions haven't been developed and when they are developed they will be reviewed by Swimming Australia's lawyers before we approach Nick.

Tasker believed the incident was damaging to swimming's clean image. 'We do pride ourselves on being a role-model sport. We actually have athletes who want to be role-models. And when something like this happens it affects the whole sport. It affects swimmers within the sport. I know for a fact that there are people on our national team; some of those may be in the Olympic team but they have expressed their disappointment to the head coach.

Asked if the champion spirit dictated a little 'fire in the belly' approach to life, Tasker said: 'Being an elite athlete is about working really hard at controlling all the things that you can control. And over the years I could rattle off 20 names of athletes who have shown amazing courage in the swimming pool and why have they done that is because they're fiercely competitive, absolutely rabid competitors, but they don't take that into their general lives.

Cowley is said to be in 'a lot of pain ... really quite shocked about it'. Tasked had no idea what had sparked the alleged fight.