China's auto sales rose 9.9 percent year-on-year in June, an industry group said Wednesday, with growth weakening from May as the world's biggest car market loses steam.

Total vehicles sales for June stood at 1.58 million units, the China Association of Automobile Manufacturers said in a statement.

That compared to a 16 percent year-on-year rise in May to 1.61 million vehicles, previous data showed.

"The domestic economy still faces downward pressure," the group said. "There is a lack of momentum for rapid growth of auto sales in the short term."

For the first six months of the year, China's auto sales rose 2.9 percent from the same period last year to 9.60 million units, the group said.

The nation's auto sales began to slow last year after the government rolled back buying incentives and some cities imposed tough restrictions on car numbers to ease chronic traffic congestion and pollution.

The southern city of Guangzhou earlier this month imposed a cap on the number of cars allowed to be sold, spurring worries more cities could follow suit.

China's economy has also been weakening, recording 8.1 percent growth in the first quarter of this year, its slowest pace in nearly three years.

The domestic auto sector is still in "consolidation mode" based on production and sales for the first half, the industry group said.

But foreign car makers in China have fared better, helped by name recognition and perceptions of higher quality, analysts say.

US auto giant General Motors said last week its China sales for the first half of this year jumped 11.3 percent from a year earlier to a record 1.42 million vehicles.