A manufacturing Purchasing Managers' Index of 50.4 in April, down from 51.6 in March, indicated slowing factory output.

The HSBC PMI figures have been above 50 for six consecutive months. Anything above 50 indicates expansion, below indicates contraction.

Output and new orders in April expanded at weaker rates, while new export orders contracted for the first time since the beginning of the year.

"The slower growth of manufacturing activities in April confirmed a fragile growth recovery of the Chinese economy as external demand deteriorated and renewed de-stocking pressures built up," said Qu Hongbin, chief economist for China at HSBC.

"It is likely to invite more policy responses in the coming months," Qu added.