China's factory activity remained in expansion territory in April, staying above the 50-point boom-bust line for a second consecutive month, according to official data.

China's official purchasing managers' index for the manufacturing sector came in at 50.3 in April, edging down 0.1 percentage point from March while remaining above the 50-point mark that separates expansion from contraction, data from the National Bureau of Statistics showed on Thursday.

Huo Lihui, an NBS statistician, said the continued expansion was underpinned by sustained growth in both production and market demand among manufacturers.

The sub-index for production rose 0.1 percentage point from March to 51.5 in April, while the new orders gauge fell 1.0 percentage point to 50.6, though both remained above the 50-point mark, the NBS reported.

Meanwhile, PMI readings for major industries extended expansion. High-tech manufacturing, for instance, posted a PMI reading of 52.2 in April, up 0.1 percentage point from March, while equipment manufacturing recorded a PMI of 51.8, up 0.3 percentage points from the previous month.

By enterprise size, the sub-index for large enterprises came in at 50.2 in April, down 1.4 percentage points from the previous month. The readings for medium-sized and small enterprises stood at 50.5 and 50.1, respectively, up 1.5 and 0.8 percentage points from March, with both returning to expansion territory, the NBS said.

However, non-manufacturing activity softened during the month. China's non-manufacturing PMI — which includes sub-indexes for service sector activity and construction — came in at 49.4 in April, down 0.7 percentage points from the previous month, NBS data showed.

The country's official composite PMI — which encompasses both manufacturing and non-manufacturing activities — stood at 50.1 in April, down 0.4 percentage points from March, but remaining above the 50-point mark, according to the NBS.