After having eased in recent months, Spain's rates of growth in services business activity and new orders improved in December.
Confidence regarding the 12-month outlook for activity also strengthened.
Rising workloads led companies to increase their staffing levels markedly again.
On the price front, input costs continued to rise sharply while firms raised charges in line with improving customer demand.
The headline seasonally adjusted Business Activity Index ticked up to 54.6 in December from 54.4 in November, signalling a slightly sharper increase in activity over the month. This followed two successive months in which the rate of growth had slowed.
Activity rose markedly at the end of 2017, extending the current sequence of expansion to 50 months.
Transport & storage was the best-performing sector, seeing the fastest increases in both activity and new business. All but one of the monitored categories saw output rise, the exception being hotels & restaurants.
General improvements in economic conditions were reportedly behind rises in both activity and new business, while expanded sales teams were also mentioned. New business increased at a marked pace that was sharper than that recorded during November.