Paris - The International Swimming Federation (FINA) has weighed in on a swimsuit row, declaring swimmers cannot wear anything at all under their costume to protect their modesty, it was reported on Thursday.

The move comes after Swede Therese Alshammar became the first swimmer to be stripped of a world record after Australian judges ruled she had been wearing two swimsuits when she bettered her existing world mark in the 50 metre butterfly in Sydney.

Alshammar slammed the decision, declaring the rules sexist and saying she thought she was allowed to wear a "modesty suit" under her skin-tight racing suit.

Officials at the Australian Swimming Championships had said women were allowed to wear bikini bottoms under their suits for modesty purposes but not a full suit because it may provide extra buoyancy in the pool.

However, Cornel Marculescu, executive director of the sport's governing body, FINA, reportedly contradicted the Australian ruling by stating that swimmers were not allowed to wear anything under the main swimsuit, specialist website swimnews.com reported.

"That means that nothing must be worn underneath," Marculescu told the website. "One suit only. That's it."

FINA this month adopted new rules on the revolutionary swimsuits, which led to 105 world records being set in 2008 over long-course and short-course distances.

The measures were introduced after claims that the new hi-tech suits provide an unfair advantage and that technology was taking over from sheer individual talent.

Under the new rules, swimsuits cannot cover the neck and cannot extend past the shoulders or ankles.

They must also be a maximum one millimetre thick and cannot be custom-made for or adapted by individual swimmers.