The Irish Tourist Industry Confederation said it is disappointed with figures that show an 18% drop in visitor numbers for May compared with the same period last year.
The figures from the Central Statistics Office show a fall of 150,000.
Read the full CSO report
The number of visitors from Britain, Ireland's largest source of tourists, dropped by 23%, while the number of visitors from continental Europe fell by 20%.
There was no change in the North American tourist market from last year.
Overall visitor numbers for the first five months of 2009 are down by over 10% on the same period last year.
