FINA has revised its list of approved swimsuits with a number of controversial high-tech suits permitted.

The revision comes after the world governing body could not prove conclusively that the garments provided an advantage.

More than 100 world records were broken in 18 months, leading FINA to conduct a review of swimsuits which concluded last month with 10 high-tech suits rejected.

However, the Jaked 01 and the Arena X-Glide - recently worn in world record swims by Frenchmen Fred Bousquet and Alain Bernard - and their ilk have now been reinstated, with FINA unable to prove conclusively that air-trapping, and therefore improved buoyancy, occurs in the water.

FINA believe more time is required to analyse the swimsuits and they will now be permitted for use throughout the remainder of 2009 and in the World Championships in Rome next month, with the garments checked in the call room prior to competition.

A statement read: "The executive found that the evidence of 'in use' air trapping effect is complex and that it would require considerable time to create and implement comprehensive control mechanisms and test methods which would permit to establish the effect with absolute certainty in connection with particular swimsuits.

"In a transitory period where the industry had little time to anticipate the requirements, it is also important to take into account that the outcome of the approval process can have substantial impact on existing production and stocks.

"Therefore, in cases where there was a reasonable doubt as to the effect, such doubt had to be taken into account in the decision concerning the respective swimsuits."

The statement added: "To secure a level-playing field, the swimsuits approved will be available to all swimmers at the FINA World Championships in Rome from July 17-August 2, 2009.

"The approved swimsuits will be labelled and will be checked in Rome prior to competition.

"The rules regarding shape, use of only one swimsuit and no taping will be strictly applied and controlled in the first call room.

"FINA will continue the process of controlling the evolution of swimsuits and will issue new rules including new criteria for 2010."