US Olympic broadcaster NBC asked for the change to ensure the finals are screened in prime-time in America.

The proposal has met with widespread opposition around the world, with even USA Swimming expressing doubts.

The International Olympic Committee's executive board has said it will make a final decision later this year.

The move would showcase swimming for eight nights in the US, but it would air at less desirable times in Europe, Asia and Australia.

Swimming Australia and Channel Seven, which holds Australian TV rights to the Games, have written letters opposing NBC's request.

"This is about the integrity of the sport and allowing athletes to perform to their maximum," Swimming Australia chief Glenn Tasker told The Australian newspaper.

"To force this on them would be grossly unfair and would produce a second-rate meet."

Mark Schubert, national team coach and general manager for USA Swimming, said: "It would be a very radical change, and we're very anxiously awaiting the final schedule."

Fina chief executive Cornel Marculescu said swimming's world governing body preferred to maintain the traditional schedule of evening finals and morning preliminaries.

He said: "We have an opinion, but we have to keep good relations with the IOC and support them as much as we can.

"The final decision is with the IOC executive board."