China's biggest carmaker Shanghai Auto Industry Corporation (SAIC) has reported a rise in net profit of more than six percent in the first half on stronger sales.

The firm made 15.06 billion yuan ($2.25 billion) in the first six months of the year, SAIC said in a statement last week to the Shanghai stock exchange, where it is listed. 

The figure was 6.31 percent higher than the 14.17 billion yuan in the same period last year.

SAIC sold a total of three million cars in January-June, up 4.9 percent year-on-year, according to the statement, maintaining its position as the country’s biggest auto manufacturer by sales. 

The company said a “stable growth trend” in the domestic auto market supported its earnings.

But investors were unimpressed. SAIC shares were down 1.60 percent in early afternoon trading on Monday in Shanghai.

Car sales in China, the world's biggest auto market, increased in 2015 at their slowest rate in three years, rising less than five percent annually to 24.6 million units as the world's second-largest economy lost momentum.

But they jumped 8.14 percent year-on-year in the first six months to 12.83 million, according to the China Association of Automobile Manufacturers. 

China's economy expanded 6.7 percent in the second quarter of this year, the same as the previous three months but down from 6.9 percent for all of 2015.