FAW Car Co, a unit of one of China's three largest auto makers, First Automotive Works, estimated on Saturday that its net profit in the July-September quarter fell about 5 percent from a year earlier.

That would mark a major deterioration from the first half of this year, when FAW, which makes cars with Mazda Motor Corp, posted a 206 percent rise in net profit.

In the third quarter of last year, the company made a profit of 356.5 million yuan ($52.2 million).

FAW Car did not give a reason for the third-quarter profit drop. But a slowing economy has hit Chinese auto demand hard in recent months; country-wide passenger car sales shrank from a year earlier for a second month in a row in September.

The company is due to report full third-quarter earnings late this month.