Among 21 specific industries surveyed, 12 of them saw their PMIs register above 50 in May, indicating expansion in business activity. The number was 9 in the previous month.
The sub index for production marked 49.7 in May, 5.3-percentage-point higher than April, and the new order index rose from 42.6 to 48.2.
"This shows that manufacturing production and demand have recovered in varying degrees, but the recovery momentum needs to be strengthened," said Zhao Qinghe, a senior NBS statistician.
The non-manufacturing segment was up by 5.9 percentage points to 47.8, NBS data shows.
Since March, a new wave of COVID-19 spreading across China has slowed down business activity and production, as northeastern Jilin Province, eastern Yangtze River Delta where Shanghai is located and the capital Beijing have implemented different degrees of closed-off management.
While the COVID-19 situation turned better in May, the virus-containing measures were eased and production gradually resumed in those places.
The municipal government of Shanghai has said the 25 million-people city will gradually restore the normal order of production and life across the city with routine COVID-19 prevention and control measures from June 1 to mid-late June.
Last week, Chinese Premier Li Keqiang emphasized 33 measures to stabilize the economy that were proposed at a previous State Council executive meeting, including a $21-billion tax cut plus more bonds to fund infrastructure spending.
"... we expect the official manufacturing PMI to rebound to 50.3 in June, returning to expansionary territory for the first time since February," Nomura Securities said in a note.