A revolutionary bodysuit has divided the world of swimming into the haves and the have-nots ahead of the Beijing Olympic Games, testing relationships between federations, athletes and rival suppliers.

Australian and US swimmers and others wearing the Speedo LZR Racer suit have set 38 world records since its introduction in February. Australian Libby Lenton said it made her feel she was swimming downhill.

As the buzz has grown - an LZR is even on display at the Metropolitan Museum of Art in New York in an exhibit on superheroes - swimmers using other equipment are weighing the merits of breaking existing contracts and switching to Speedo.

And rival manufacturers are rushing to upgrade their bodysuits to a level that will satisfy swimmers and federations desperate to win medals in Beijing in August.

Perhaps the highest-profile revolt was by Japan's Kosuke Kitajima, who won 100-metre and 200-metre gold in the breaststroke at the Athens Olympics in 2004. His move forced the Japanese team to ditch its contract with Mizuno and two other suppliers and allow swimmers to race in LZR suits.

The Italian swimming federation, which has an agreement with Arena, said its athletes can break the contract if they are prepared to pay a fine.

And German swimmers are expecting Adidas to upgrade its suit in what former world record holder Britta Steffen called a technological race that "seems a bit like Formula One."

Waist-to-knee

Introduced 15 years ago, bodysuits have drawn charges of unfair advantage ever since. In 2000, Australia's most famous swimmer, Ian Thorpe, demanded to wear an Adidas suit at the Sydney Games, despite his federation having a contract with Speedo.

They range from full suits to torso and waist-to-knee suits, and have carried names like Acquablade, Fastskin, Sharkskin and Jetconcept.

The LZR suit, designed with help from US space agency NASA, keeps swimmers in a corset-like grip which allows the swimmer to maintain the best body position in the water for longer and reduce drag.

Some reports have credited it with reducing swimming times by up to 2 percent, although Speedo officials said that is impossible to verify.

Speedo executives say they are puzzled but amused by the flap.

"The Speedo LZR Racer is not a miracle suit," said Speedo Vice President Craig Brommers. "It has set zero world records."

Nonetheless, Speedo was doing everything it can to "rule the pool" in Beijing, Brommers said.

Stu Isaac, a senior vice president with the Speedo division of Warnaco Group, said Speedo was just doing what sports scientists are doing everywhere - improving performance.

"We put as much effort into making the suit better as the swimmers are putting in in the pool," Isaac said.

In the United States, the swimming team allows athletes to sign their own marketing deals. But head coach Mark Shubert said swimmers who want to go to Beijing should wear Speedo at the ongoing US trials "or they may end up at home watching on NBC."