A worker cut steel bars at a steel plant in Ganyu, Jiangsu province June 9, 2014. [Photo/Agencies]

Activity in China's factory sector expanded at its fastest pace in 18 months in July, a preliminary HSBC survey showed on Thursday, as a raft of government stimulus measures kicked in.

The HSBC/Markit Flash China Manufacturing Purchasing Managers' Index rose to 52.0 in July from June's final reading of 50.7, beating a forecast of 51.0 in a Reuters poll.

It was the highest reading since January 2013, and above the 50-point level that separates growth in activity from contraction for the second consecutive month.

A sub-index measuring new orders, a gauge of demand at home and abroad, hit a 18-month high of 53.7, while the sub-index for output also rose to a 16-month high in June.

The final Markit/HSBC manufacturing PMI for July is due on Aug. 1.

China's economy grew slightly faster than expected in the second quarter as a burst of government stimulus paid dividends, but analysts said Beijing will likely need to offer further support to meet its growth target of around 7.5 percent for 2014.

China June HSBC PMI shows first expansion in six months	China's HSBC flash PMI shows expansion in June