The business services, financial services and the IT sectors have all reported growth in January, the eighth successive month of expansion.
Seasonal factors eased the speed of growth slightly the NCB Purchasing Managers' Index said the services sector fell to 57.3 from 58.8 in December.
A reading above 50 indicates expansion, a reading below 50 indicates contraction. The index is based on data from 600 companies.
According to the data the hospitality sector shrank at its fastest pace in a year, due largely to seasonal factors.
However, the Index revealed renewed optimism with new business levels expanding for the fourth time in five months to reach the highest level since August 2000.
The cost of doing business also rose last month to 58.8 from 57.9 - due to increasing wage rates, higher heating bills, insurance costs and telecom charges.
The financial services sector faced a sharp rise in cost inflation in January. The report noted that while there were reports of inflationary wage pressures, January's data reflected the impact of seasonal bonus payments.