China's manufacturing activity may have expanded the most in two years in January thanks to robust demand amid the recovery of the world's second-largest economy, an HSBC survey showed this morning.

The HSBC Flash China Manufacturing Purchasing Managers' Index, the earliest available indicator of China's industrial performance, climbed to a 24-month high of 51.9 in January, up from 51.5 in December. A reading above 50 means expansion.

It may be the third consecutive month that the index, which is slanted towards private and export-oriented firms, stayed in the territory of expansion.

Qu Hongbin, chief economist for China at HSBC Holdings Plc, said the January's HSBC China manufacturing PMI may herald a good start to the new year.

"Thanks to an increase of new orders, manufacturers accelerated production by additional hiring and more purchases," Qu said. "Despite a weak external demand, the restocking process by domestic enterprises is likely to add steam to China's ongoing recovery in the coming months."

China's economic growth quickened to 7.9 percent in the fourth quarter of last year, ending a seven-quarter slowdown after the government relaxed its monetary policy and fast-tracked some big investment projects.

However, the world's second-largest economy may continue to be impacted by a faltering global economy and a cooling housing market at home, some analysts warned.

The HSBC Flash China Manufacturing PMI is an estimate of the final data to be released on February 1. It is based on 85 to 90 percent of total PMI survey responses.