China's automobile output and sales both exceeded 11 million units during the first half of 2014, underlying great inventory pressure for car dealers, according to data from the China Association of Automobile Manufacturers (CAAM) on Wednesday.

Auto production rose 9.6 percent from a year ago to 11.78 million units from January to June, accelerating from 9.4-percent growth during the January-May period.

However, sales of vehicles increased only 8.4 percent year on year to 11.68 million units, slowing further from an increase of 9 percent seen in the first five months, according to CAAM.

The economic slowdown weighed heavily on growth in both auto output and sales during the first half, compared with 12.83-percent growth in output and 12.34-percent growth in sales in the same period of last year.

The CAAM data were calculated from the wholesale level after automakers sold their cars to dealers, indicating retail sales figures might be even worse for dealers, according to CAAM.

The China Automobile Dealers Association said earlier this month that dealers' inventories have climbed to their highest level in nearly a year.

A decline in the commercial vehicle market stalled growth in the world's largest auto market, as output of commercial vehicles dipped 0.6 percent year on year, while sales of commercial vehicles fell 3.2 percent, according to CAAM.

A total of 9.6 million passenger cars were sold in the first six months, up 12.1 percent from a year earlier.

China's domestic auto brands recorded their lowest level of market share since 2009, accounting for 37.7 percent of the entire market, down 3.5 percentage points from a year ago.

China has remained the world's largest auto market and producer for five consecutive years, with production and sales both exceeding 20 million units for the first time in 2013.