TOKYO » Toyota will recall 270,000 Prius hybrid vehicles over brake problems in the United States and Japan, a report said today, while the beleaguered auto giant launched an investigation into possible problems with the brakes in its luxury Lexus hybrid.

About 450 of the cars have been sold in Hawaii, according to Servco Pacific Inc., which distributes Toyota models to dealerships statewide through its Toyota Hawaii division.

“;I wouldn't call it a brake failure,”; said Mark Fukunaga, Servco chairman and chief executive officer. The brakes “;do not respond as fully as you might expect,”; primarily on uneven road surfaces.

Rather, there is some hesitation in the brakes' response and transition between the battery-regeneration function of the brakes and the hydraulic system that actually stops the car, he said. “;It is a fairly simple software fix,”; he said.

Owners are encouraged to contact their dealers with any concerns, Fukunaga said.

The recall affects the new, 2010 Prius hybrid model, and Toyota Motor Corp. will soon notify Japan's transport ministry and the U.S. Department of Transportation of the recall, Japan's top business newspaper, Nihon Keizai, reported today. The affected models were built in Japan.

Takayuki Fujimoto, a transport ministry official, said the government has yet to receive a recall notice from Toyota. Toyota cannot announce a recall in Japan until it notifies the ministry.

Toyota spokeswoman Ririko Takeuchi said today that Toyota had not yet decided whether to recall the Prius. “;Nothing has been decided on whether we will recall or not,”; Takeuchi said.

The new Prius hybrid went on sale in Japan and the United States in May 2009.

More than 170,000 of the new Prius models have been sold in Japan, with around 103,000 sold in the United States since May.

Toyota, reeling from massive global recalls of 4.5 million vehicles involving faulty gas pedals, acknowledged design problems yesterday with the brakes in its prized Prius.

Complaints about braking problems in the Prius—the world's top-selling gas-electric hybrid—have been reported in the United States and Japan, combining to some 180.

Takeuchi said Toyota has launched an investigation into the luxury Lexus HS250h hybrid model for possible brake problems in Japan and the United States as the vehicle uses the same brake system as the new Prius hybrid.

“;We want to ensure safety for our customers,”; Takeuchi said. Toyota has not received any complaints about the Lexus HS250h, she said. The luxury HS250h went on sale in July in Japan, and in September in North America.