Chinese auto makers rolled out 9.04 million vehicles in 2007, up 22.9 percent year on year, said the country's top economic planner, the National Development and Reform Commission (NDRC).

The figure included an output of 4.95 million passenger vehicles, an annual jump of 25 percent, Zhu Hongren, the NDRC deputy economic performance department director, told a news conference in Beijing on Monday.

He didn't elaborate on the other vehicles produced.

The country's auto output is expected to exceed 10 million units this year while passenger car output will likely top five million units, Zhu predicted.

He added, since quantity was not a problem anymore, auto producers should increase their focus on quality.

Compared with their international counterparts, China's auto makers are still small in terms of production scale and behind in technology. In addition, the country's auto boom has created growing problems, such as increasing traffic jams and pollution, despite the greater convenience.

To combat pollution in the capital, Beijing imposed the Euro-III car emission standard. Despite this, exhaust fumes emitted by the city's 2.8 million motor vehicles remained one of its primary sources of pollution.