China's auto sales fell 1.1 percent in October from a year earlier to 1.52 million units, an industry group said Wednesday, marking the first decline in five months.

The fall was due to a sharp drop in commercial vehicle sales last month -- down 9.9 percent from a year earlier -- the China Association of Automobile Manufacturers (CAAM) said in a statement.

Sales of passenger vehicles -- which account for the bulk of sales in the world's biggest auto market -- rose an anaemic 1.4 percent on year to 1.22 million units, the semi-official group said.

Month-on-month, passenger vehicle sales declined 7.5 percent, it added.

Total sales topped 15 million units in the first 10 months of the year, CAAM said, without providing an exact number.

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.

CAAM has said it expects sales growth for 2011 to be just five percent, down from an earlier forecast of 10-15 percent.

Monthly auto sales dipped 0.25 percent in April, their first year-on-year decline in more than two years, followed by a fall of 3.98 percent in May, before rebounding the following month.