Japanese companies are used to innovate-or-perish technology wars, but never one like this.

With a little less than three months before the world's greatest swimmers plunge into Beijing's Olympic pool, Japan's “big three” sportswear makers have a deadline that they are all but certain to miss: improve your swimsuits by the end of this month, or risk international humiliation.

It is a fight that might have been lost already: asked whether sponsored swimmers might defect to a better swimsuit, a spokesman for Asics, Japan's largest sportswear company, told The Times that there were “various possibilities” open to the athletes.

Swimsuit technology had been relatively slow-moving, bar a few improvements in fabric or shape, but the millennium has changed all that.

Now, Japan's leading global sportswear makers - Asics, Descente and Mizuno - are faced by a technology leap by Speedo, the Nottingham-based market leader.

Blame is being directed at the Speedo Fastskin LZR, a bodysuit that sucks muscles into the perfect swimming shape.

Nineteen world swimming records have tumbled since February and all but one have been broken by swimmers, of various nationalities in the new Speedos.

The costume has been endorsed by the International Swimming Federation and, in a provocative challenge to Japan's domestic swimwear makers, Norimasa Hirai, who trained Japan's gold medal-winners at the Athens

Olympics in 2004, declared that any swimmers not wearing the suits in international events from now on would be “battling with a handicap”.

The problem for Japan's swimmers, several of whom are favoured to win medals in Beijing, is that their sponsorship deals are laden with national pride.

They are contractually bound to wear swimsuits made by their Japanese backers, but they worry that they will lack the necessary smoothness through the water.

Moreover, many have cheated on their sponsors at recent competitions, using Speedos to beat their best times by almost a second.

Now the secret is out, the Japanese Swimming Federation has given Asics, Mizuno and Descente until May 30 to produce a competitive costume or risk a slew of embarrassing defections by the national squad.

The companies have vowed to throw everything at the effort, but have told The Times that the deadline may simply be too close. “It is very difficult to see what we can do at this stage,” a Descente spokesman said.

Nor will they find much sympathy from rivals. “I think the criticism [from rivals] is sour grapes and understandable,” Mark Schubert, the United States's swimming team head coach, said recently.

“Speedo's put millions into research and other companies haven't. They're going to be kind of left holding the bag at this Olympics.”

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