In a restructure of the traditional schedule swimming finals will start after 10pm local time, about three hours later than the regular session start at previous games and major international meets. Some medals will be decided after midnight.

The move has largely come at the behest of American network NBC, which paid $4.4 billion for the rights to Rio and Tokyo (2020). Later finals better suit the US primetime audience and the hefty price ensured NBC was given a strong hand at the negotiating table.

But it has come to the dismay of many Australian athletes and coaches, including world champion and Olympic gold medallist Cate Campbell, who said the swimmers would pay the price for corporate manoeuvring and the shift would impact performances on the biggest stage.

Australian head coach Jacco Verhaeren has already lashed out at the move, which was confirmed by the IOC this month, saying it showed little respect for athletes, many of whom would usually get out of bed at 4am, not settle down for the night.

Campbell said the Games should be built on elite performance and not based solely on the needs of sponsors and major media partners.

"I think that it's very disappointing when the athletes have to bear the consequences of corporate politics. We do normally bear the brunt of it," Campbell said.

"Everyone will be in the same boat, I understand that. But I still believe that it was not the right decision. The Olympic Games is about performance. Racing at that time of night could jeopardise some people's performances.

"Jacco said it was disrespectful for athletes and I completely agree with that. We will compete regardless of course but I think that it's a little bit sad when money stands in the way of Olympic performance."

The Australian Olympic Committee president John Coates has been left far from impressed but has begun to consider contingency plans to ensure the swimming team, which fell short of expected goals in London, was adequately rested and prepared to race.

"I know they (the AOC) have contingency plans to move the swimmers to quieter parts of the village, to get blackout curtains, ear plugs and eye masks. We have a great team around us and we'll be as prepared as we possibly can," Campbell said.

Campbell, the 100m freestyle world champion and London gold medallist in the 4 x 100m relay, continues her recovery from shoulder surgery, in which a centimetre of bone was shaved from her collarbone joint.

She competed through the Commonwealth Games and Pan Pacs with the injury, which was scraping away cartilage and irritating nerves every time she fully extended on a stroke.

A return to the pool in January remains the goal but Campbell has realistic expectations about the FINA world championships in Russia in July. She concedes she may not even make it through qualifying in April given the level of competition, which includes sister Bronte.

"I've come to terms with the fact that I may not be 100 per cent for world champs. But in the big scheme of things, Rio is the ultimate goal," Campbell said.

"I think it's unlikely I will be at 100 per cent by then (world championships). And of course this is assuming I make the team. I have to compete in one of the most competitive events on the calendar. It will be tough to make that team in April."