China's official factory purchasing managers' index rose to 49.8 in September from 49.2 in August, the National Bureau of Statistics said on Monday.
August marked the lowest reading since November 2011, in the latest sign that growth in the world's second-biggest economy is struggling against cooling exports, factory output and fixed asset investment.
Economists polled by Reuters this week had expected September official PMI to rise to 49.8.
A PMI reading below 50 suggests factory activity contracted, while a number above 50 points to expansion.
A PMI survey published earlier by HSBC ticked up to 47.9 in September from a nine-month low of 47.6 in August, pointing to a month in which a slide in the rate of economic growth was halted but not reversed.
(Reporting By Lucy Hornby)