Growth in the country's services sector slipped to a seven-month low in June as new domestic business orders expanded at a slower pace, but the sector continued to expand.
Investec's Services Purchasing Managers' Index (PMI) slipped to 57.6 in June from 59.5 in May, for its lowest reading since November last year.
However, the index has not fallen below the 50 mark that separates growth from contraction since June 2012, when Ireland was halfway through a three-year bailout.
The services sector covers areas as diverse as communication, financial and business services, IT and the tourism trade.
Ireland was the best-performing economy in the European Union for the third year in a row last year, despite concern that it is the country most exposed to the fallout from the Brexit vote.
Earlier this week, Investec said its manufacturing PMI for June reached 56, indicating that the manufacturing sector was growing at its fastest since July 2015.
Taken together, the two surveys show "very solid overall expansion" in the Irish private sector in the first half of the year," Investec Ireland's chief economist Philip O'Sullivan said.
The forward-looking business expectations subindex for services indicated that eight times as many respondents expected improvement in the coming 12 months as expected deterioration.
"Given the generally improving international backdrop, we think that this optimism is warranted," Mr O'Sullivan said.