Vehicles sales totaled 1.98 million units last month, the China Association of Automobile Manufacturers (CAAM) told a press conference in Beijing. Passenger vehicle sales rose 6.4 percent while commercial vehicle sales slumped 16 percent.

During the first nine months of 2014, China's vehicle sales rose 7.0 percent from a year earlier.

CAAM has forecast that the market will expand 8.3 percent this year, slowing from last year's 13.9 percent pace.

"China already has a huge auto market, and with more cities expected to restrict auto sales to fight pollution, it's natural for growth to slow down," said Li Xiangfeng, an analyst at Shanghai-based consultancy ISE.

"The market cannot grow at double-digit pace forever," he said, adding that the slump in commercial vehicle sales might be cased by a slowing economy.

In September, Japanese carmakers Nissan Motor Co Ltd (>> Nissan Motor Co Ltd) and Honda Motor Co Ltd (>> Honda Motor Co Ltd) both posted their third consecutive monthly decline in China sales, registering decreases of 20 percent and 23 percent respectively.

Nissan attributed the decline to sluggish sales of commercial vehicles and increased competition while Honda said dealers had been clearing inventory ahead of the launch of two new models later this year.

On the other hand, sales of German brands have continued to be robust. Premium carmaker BMW (>> Bayerische Motoren Werke AG) posted a 17.9 percent growth during the first nine months while Daimler AG's (>> Daimler AG) Mercedes Benz said its China sales jumped 30.5 percent in September.

Volkswagen AG's (>> Volkswagen AG) premium brand Audi posted a 13 percent increase in China sales in September.

(Reporting by Beijing Newsroom; Writing by Samuel Shen; Editing by Kazunori Takada and Sunil Nair)