TOKYO — Double Olympic champion Kosuke Kitajima was among five swimmers to break Japan national records in Speedo's LZR Racer swimsuit Friday, raising doubts about the contractual obligation for Japan swimmers to use domestically produced suits at the Olympics.

Kitajima, who won the men's 100 and 200-meter breaststroke at the 2004 Olympics, set a new national record in the 100 breaststroke at the Japan Open. His time of 59.53 seconds was 0.09 seconds better than his previous personal best, and 0.40 seconds off the world record held by Brendan Hansen of the United States.

Kitajima and all Japan national team competitors are currently obligated to wear swimsuits made by Japanese manufacturers at Beijing. The Japan Swimming Federation will meet next week to address the issue, balancing the contract against potential Olympic performance.

Since the Speedo LZR Racer was introduced in mid-February, swimmers using the suit have set 37 world records.

Last month, three Japanese sportswear makers introduced new versions of high-tech swimsuits intended to compete with Speedo's suit for Beijing. Kitajima is contracted to wear Mizuno at the games.

"I want to wear the Mizuno suit," said Kitajima. "But to be honest, after setting a new national record, I can say the Speedo is a great swimsuit."

Haruka Ueda, also a member of Japan's squad for the Beijing Olympics, set a new national mark of 1:57.75 in the women's 200 meter freestyle, taking 1.03 seconds off the previous mark.

Reiko Nakamura also clocked a new national record of 59.82 seconds in the women's 100 meters wearing the high-tech Speedo.

Takeshi Matsudo set a new national record of 1:54.42 in the men's 200 meter butterfly while Yoshihiro Okumura clocked a new national mark of 1:47.36 in the men's 200 meter freestyle.