China's factory activity returned to expansion territory in June, moving back above the 50-point mark after standing at the boom-bust threshold a month earlier, official data showed on Tuesday.

Data from the National Bureau of Statistics showed that China's official purchasing managers' index for the manufacturing sector came in at 50.3 in June, up 0.3 percentage points from the previous month.

Huo Lihui, an NBS statistician, said the improvement reflected stronger production activity and recovering market demand, with both expanding in the manufacturing sector.

The production sub-index reached 51.4 in June, 0.2 percentage points higher than the previous month, while the new orders sub-index rose 1.3 percentage points to 51.2, returning to expansion territory, the NBS said.

New growth drivers also maintained solid momentum. The PMI for high-tech manufacturing stood at 53.5 in June, compared to 52.9 in May, while the reading for equipment manufacturing reached 52.5, up from 52.1 in May, with both staying firmly in expansion territory, according to the NBS.

"Advanced manufacturing continued to make robust progress, further strengthening its role as a key driver of growth," Huo said.

In addition, non-manufacturing activity improved slightly in June. China's non-manufacturing PMI, which includes sub-indexes for service sector activity and construction, stood at 50.2, edging up 0.1 percentage points from May, as the sector's overall business climate showed signs of recovery, NBS data showed.

China's official composite PMI, which encompasses both manufacturing and non-manufacturing activities, came in at 50.6 in June, 0.1 percentage points higher than in May, pointing to a modest pickup in overall business activity, according to the NBS.