REUTERS - Therese Alshammar of Sweden was stripped of a world record on Tuesday when it was discovered she wore two swimsuits during a race at the Australian national championships.

Swimming Australia officials disqualified Alshammar after a five-hour investigation ruled she had broken the newly introduced rule on swimwear. The 31-year-old immediately lodged an appeal against her disqualification.

Alshammar broke her own 50 metres butterfly world record during Tuesday morning's heats at Sydney's Olympic pool.

She stopped the clock at 25.44 seconds, slicing 0.02 seconds off the existing world record of 25.46 she set at a meet in Barcelona in June 2007.

Alshammar was ordered to appear before Swimming Australia officials after they viewed a television replay showing her wearing two suits.

Swimming Australia banned the use of multiple swimsuits after last year's Beijing Olympics because of concerns about extra buoyancy.

The sport's world governing, FINA, introduced a similar rule last week.

The 31-year-old Swede is the reigning 50 butterfly world champion after winning the title at Melbourne in 2007 and is among the favourites to win again at this year's world championships in Rome.

Alshammar has been training in Sydney this year and was allowed to compete in the heats of this week's Australian national titles but not the semi-finals or finals.