Auto sales in China jumped 19.7 percent on-year in September, an industry group said Friday, helped by brisk demand before an extended national holiday and stronger sales of Japanese brands.

A total 1.94 million vehicles were sold in the world's largest auto market in September, the China Association of Automobile Manufacturers said in a statement.

Sales of passenger vehicles also gained 21.1 percent from a year earlier to 1.59 million last month, it said.

In the first nine months, car sales rose 12.7 percent year-on-year to 15.88 million, while passenger vehicle sales jumped 14 percent from a year earlier to 12.85 million.

The September growth came amid higher demand before the weeklong National Day holiday in early October, while strong sales of Japanese vehicles also contributed.

Sales of Japanese-brand passenger vehicles rocketed 73.7 percent year-on-year in September, the group said, without giving the total figure.

Japanese car sales plunged in September last year amid a dramatic spike in tensions surrounding a long simmering sovereignty dispute over islands in the East China Sea -- known as Diaoyu in China and Senkaku in Japan.

China became the world's largest auto market in 2009.

The nation's auto sales grew 4.3 percent annually to 19.31 million vehicles in 2012, hit by limits on numbers imposed by some cities to ease traffic congestion and tackle pollution.