Australia's triathlon team is urging Paris Olympics organisers to keep the swim leg, regardless of the water quality in the River Seine.

The persistent rain that marred Friday night's opening ceremony along the famed river is the nightmare scenario for the event.

It will raise water pollution, a nagging issue for the triathlon and marathon swimming events.

But the Australians made it clear if it was up to them, the 1.5km swim will go ahead at next week's events no matter how bad the water conditions.

Asked if he would swim in the Seine on Saturday, despite the weather, Australia's top medal contender Matt Hauser said "bloody oath I would".

"We're expecting a triathlon. It's good to go at this stage. Swim familiarisation might not go ahead tomorrow, just for the safety of the athletes," Hauser said on Saturday morning.

"The organisers are taking care of everything and we're confident Tuesday and Wednesday are going to go ahead as planned.

"Me being a strong swimmer, obviously I want a triathlon - even the strong runners and the weaker swimmers want a triathlon.

"It's going to be a true test of an Olympic champion. It's got to be a triathlon.

"All the signs are showing that it is going to be a triathlon, which is great."

The men's triathlon is scheduled for Tuesday, with the women taking on the same 1.5k swim, 40km bike and 10km run in the heart of Paris the following day.

The mixed team relay, also featuring the Seine, is set for August 5.

"We've actually swum in pretty bad water before. We've taken all the precautions, we've taken some vaccines and stuff like that," Hauser said.

"If anything does arise, we're prepared for it."

Organisers could change the triathlon to a bike-run duathlon and move the marathon swimming to the rowing venue.

"Whatever is thrown my way, I will be prepared for it. If it is a duathlon, whatever, we'll race it," Hauser said.

"It will be a big shame, but we really believe it's going to be a triathlon."

The rain will most likely mean a strong current, which will suit the strong swimmers such as Hauser on the out-and-back course.

Teammate Natalie Van Coevorden has swum in the Seine before and, like Hauser, is keen for the format to remain as planned.

"I swam here last year and it's fine ... we're very capable of getting on with any conditions," Van Coevorden said.

Hauser is coming off a win in Hamburg a fortnight ago and is among the big names at his second Olympics.

"Confidence is important, but also knowing that you have the competence, that you do it day-in, day-out, you've been training three-plus years for this," he said.