Kitajima wore the bottom half of a controversial swimsuit

Japanese swimmers at the Olympics will no longer face restrictions on the swimsuits in which they compete.

Double Olympic champion Kosuke Kitajima set a world record in the men's 200m breaststroke at the Japan Open on Sunday, wearing Speedo's LZR speedsuit.

Kitajima clocked 2 minutes 7.51 secs, slicing a second off the previous best set by Brendan Hansen of the US.

"It has been decided Olympic swimmers will be free to select any suit," said Swimming Federation head Kazuo Sano.

World swimming records have tumbled over the last few months, almost all by swimmers wearing the LZR suits, which the British company says reduces drag, muscle oscillation and skin vibration.

Sixteen national records were broken at the Japan Open by swimmers wearing the suits.

Until Tuesday, Japanese Olympic swimmers were obliged to wear products supplied by one of three Japanese firms - Mizuno, Asics and Descente.

Some athletes have hit out at what they see as the overblown publicity surrounding the product.

At the Japan Open, Kitajima was seen wearing a T-shirt outside the pool with emblazoned letters reading "I am the swimmer," in English, Japanese and Chinese, according to news agency AFP.