Toyota Motor Corp's China sales fell about 40 percent in September from the year before, while those of rivals such as Hyundai and BMW jumped, underscoring how badly Japanese brands have been hit by a territorial row between the two countries.

Showroom traffic and sales have plunged at Japanese car makers since violent protests and calls for boycotts of Japanese products broke out across China in mid-September over the Japanese government's purchase of a group of disputed islands in the East China Sea from their private owner.

A prolonged sales hit of this scale could threaten profit forecasts at Toyota, Nissan Motor Co (7201.T) and others as China, the world's biggest car market, makes up a bigger portion of their global sales.

Toyota sold about 50,000 cars in China in September, a senior company executive told Reuters on Friday, speaking on condition of anonymity. That would be down from about 86,000 in September 2011 but better than the figure reported earlier by Japan's Yomiuri newspaper, which said sales halved from the 75,000 sold in August.