Growth in China's manufacturing sector continued to accelerate in May, rising to the highest level this year and adding to signs of a stabilizing economy, official data showed on June 1.

The purchasing managers' index (PMI) increased to 50.8 in May, up from 50.4 in April, according to data released by the National Bureau of Statistics (NBS) and the China Federation of Logistics and Purchasing (CFLP).

The reading, which inched further above the 50-point level marking monthly expansion in factory activity, indicated a pickup in China's manufacturing sector and the economy as a whole.

This is the third consecutive monthly uptick in the widely watched data. The index, seen as one of the key indicators of economic performance, began to climb in March after three consecutive months of decline.

Zhang Liqun, a researcher at the Development Research Center of the State Council, pointed to the improving data as an indication that "the economy is continuing to stabilize, and this trend is becoming evident."

China's non-manufacturing activity further expanded in May, with the sector's PMI rising to 55.5 from 54.8 in April, according to data released by NBS and CFLP on June 3.

The non-manufacturing PMI tracks activity in sectors including construction, software, aviation, railway transport and real estate.

The rise marks the second straight month of improvement, following a 0.3-percentage-point rebound in April and a decline in March. In January, the index hit its lowest level in more than a year at 53.4.

Business activity in the real estate sector remained lackluster. The sub-index for the property sector still fell below the boom-bust line of 50, with its business outlook sub-index down for three months straight.