BEIJING, Dec. 31 -- China's non-manufacturing activity continued to expand in December, with the purchasing managers' index for the sector reaching 50.4, the National Bureau of Statistics said Sunday.

A reading above 50 indicates expansion, while a reading below reflects contraction.

The service sector sub-index stood at 49.3 in December, unchanged from the previous month.

The business activities in sectors such as postal, telecommunications and financial services expanded steadily in December, with their respective sub-indexes exceeding 55, the NBS data showed.

In December, enterprises became more confident in the service sector's recovery, with the sector's sub-index for business expectations edging up 0.1 from the previous month to 59.4.

This month, the construction sector maintained robust growth, with its sub-index for business activities standing at 56.9, up 1.9 from November.

The sub-index measuring expectations for activities in the construction sector increased by 3.1 from November to 65.7, indicating optimism among construction enterprises.