Toyota Motor Corp has been hit by over 100 complaints in the United States and Japan about brake problems with the popular Prius hybrid, the latest in a spate of quality troubles for the auto maker as it grapples with massive global recalls.

The Japanese company's sales are being battered in the US - Toyota's biggest market - after recalls of top-selling models to fix a gas pedal that can stick in the depressed position.

The new Prius gas-electric hybrid, which went on sale in Japan and the US in May 2009, is not part of the recalls that extend to Europe and China, covering nearly 4.5 million vehicles.

The US National Highway Traffic Safety Administration has received about 100 complaints involving the brakes of the Prius new model. Two involved crashes resulting in injuries.

Japan's transport ministry said yesterday it has also received 14 complaints since July last year about brake problems with Toyota's new Prius hybrid.

The 14 complaints included an accident in July 2009, in which a Prius crashed head on into another car at an intersection. Ministry official Masaya Ota said two people were slightly injured in the accident.

"The Prius driver in the accident told police that a brake did not work," Ota said. "Other Prius drivers also complained brakes were not so sharp." The complaints in Japan involve the new Prius model, and the vehicles were all made in Japan, he said.

The ministry ordered Toyota, the world's No. 1 auto maker, to investigate the complaints. The other 13 cases happened from December to January 2010. Ota said the ministry has yet to receive a formal report on the complaints from Toyota.

Toyota spokeswoman Ririko Takeuchi said the firm has received reports about the Prius complaints in North America and Japan and was now looking into the matter.

Toyota shares dived 5.7 percent to 3,400 yen (US$38) with investors dumping stocks amid the Prius woes in the US and Japan. The Nikkei index added 0.3 percent to 10,404.33 as the drop in Toyota eroded sentiment.