China has slashed official forecasts for its aviation industry this year, with both passenger and cargo volume hard hit by a downturn in global and domestic demand, state media said Thursday.

China's total air passengers -- both domestic and international -- were expected to grow eight percent in 2011, slower than an originally forecast 13 percent, the China Business News said.

China's airlines transported 267 million passengers in 2010.

Air cargo is expected to be even more affected with volume remaining flat at last year's level of 5.6 million tonnes, against a previous growth estimate of 11.5 percent, the civil aviation regulator was quoted saying.

AFP calls to the regulator, the Civil Aviation Administration of China, went unanswered.

"So far this year, the international air travel market and cargo transport market suffered from weak demand, rather than the sustained boom seen last year," an unnamed industry official told the paper.

In the first nine months of this year, China's air passenger volume grew 8.8 percent year-on-year to 219 million people, while air cargo fell one percent to 4.1 million tonnes, official figures showed.

A slowdown could spell bad news for domestic airlines and the world's plane makers, which have benefited from years of break-neck growth in China.

State-run carrier China Eastern Airlines said this week that it had foregone an order for 24 Boeing 787 Dreamliners in favour of 45 737 planes, following delays in delivery of the ultra-modern Dreamliners.

Chinese airlines will add 4,583 passenger aircraft to their fleets by 2030, according to estimates given by the state-owned aeronautics giant China Aviation Industry Corporation.

The number of air passengers in China has grown on average 15.3 percent annually over the past decade -- around three times the world average for the same period, it said.