Japanese car makers' sales in China in the first three months of the year have yet to recover fully from last year's slump, and foreign rivals are capitalizing in a market expecting 7 percent growth in 2013.

Mazda Motor Corp <7261.T> said on Wednesday that it and its partners' sales in China, the world's biggest car market, dropped 21.5 percent in the three months to March from the same period a year ago.

Earlier this week, Nissan Motor Co <7201.T> said its sales were down 15.1 percent year-on-year in the three months to March, while Toyota Motor Corp's <7203.T> fell 12.7 percent and Honda Motor Co's <7267.T> decreased 5.2 percent.

Though the figures have improved since last September, when sales plunged by around 50 percent after violent anti-Japan protests broke out in China in response to a diplomatic spat between the countries, Japanese firms continue to struggle against rivals including Volkswagen AG and General Motors Co .

Japanese automakers' collective share of China's passenger vehicle market fell to 12.5 percent at the end of February from 16.4 percent at the end of last year, according to data from the China Association of Automobile Manufacturers.

German brands in particular have taken advantage and claim 19.3 percent of the market, up from 18.4 percent. Data for March was not yet available.

(Reporting by Fang Yan and Nick Edwards in Beijing and Yoko Kubota in Tokyo; Editing by Daniel Magnowski)