A car quality report website under the General Administration of Quality Supervision, Inspection and Quarantine received 11,631 complaints in 2012, the majority of which were concerning joint-venture brands, Shanghai Securities News reported Thursday.

Complaints over joint-venture auto brands account for 65 percent of the total in 2012, exceeding the 61 percent in 2011, according to 12365auto.com.

The year 2012 saw 307 complaints over luxury cars, 2.9 percent of total valid complaints, and more than the 0.7 percent in 2011. Quality problem complaints account for 78.8 percent of the total, and 62.5 percent of the luxury cars complaints concern joint-venture brands.

Complaints about joint-venture cars involved problems with a variety of auto parts, including engines, transmission boxes and air conditioning systems.

Compared with joint-venture brands, domestic brands received fewer complaints. But the car quality report website attributed it to following reasons: the total number of domestic brands in China is less than joint-venture cars; domestic brand car owners do not use the Internet as much as joint-venture car owners, and the owners' awareness of safeguarding property rights is relatively in low level.

Car owners in China's southeastern Zhejiang province lodged the most complaints over luxury cars - 15 percent of the total. Ten areas, including Shandong, Guangdong, Beijing, Jiangsu and Shanghai, represent 72.31 percent of the total number of complaints.

The ten areas have a large luxury cars sales volume, and consumers with high awareness of their rights.

The increase in luxury car complaints came along with its bourgeoning sales in China, with its share in the car market increasing 20 percent year-on-year in 2012.

Despite the sales boom, 35.83 percent of the luxury car complaints were responded within a week, 15.64 percent within 15 days, and 14.66 percent of complaints have yet to receive responses.