Markit/ADACI's services purchasing managers' index (PMI) for Italy was up to 53.4 in June from 52.5 in May.
A reading above 50 indicates expansion in the sector.
The increase was driven by rises in new work and employment.
"PMI survey data show economic growth in Italy picking up in the second quarter from the 0.3% expansion seen in Q1. Importantly, the upturn in services activity has gathered pace in recent months alongside continued solid growth in manufacturing, with the latest increase in tertiary sector output the second-fastest since November 2010," an economist at Markit Phil Smith said.