China's auto sales rose 5.5 percent year on year to 1.65 million units in September, a report said Thursday -- accelerating for the fourth straight month.

Sales of passenger vehicles -- which account for the bulk of sales in the world's biggest auto market -- hit 1.32 million units last month, up 8.8 percent from a year ago, Dow Jones Newswires said, citing an industry group.

China, which overtook the United States to become the world's top auto market in 2009, has become increasingly important for global players such as General Motors and Volkswagen as demand in their home markets deteriorates.

Auto sales in the country rose more than 32 percent last year to a record 18.06 million units, but the sector has since lost steam after Beijing phased out sales incentives such as tax breaks for small-engine vehicles.

China Association of Automobile Manufacturers expects auto sales growth for the whole of 2011 will be just five percent, down from an earlier forecast of 10 to 15 percent.

In the first nine months of the year, car makers sold 13.6 million vehicles in the country, up 3.6 percent from the same period last year.

Monthly auto sales dipped 0.25 percent in April in their first decline in more than two years.

Sales were down 3.98 percent on the year in May but since then have rebounded, rising 1.4 percent in June, 2.2 percent in July and 4.2 percent in August.