Just over 50,000 workers reported as being agency workers in the first three months of 2019, according to figures from the Central Statistics Office.
The 50,400 employees accounted for 2.6% of the workforce.
They were more likely to be female, with women accounting for 52% of agency workers.
Two in five agency workers reported that they worked 40 hours or more per week.
72% reported themselves as being in full-time employment.
Just under a fifth of agency workers - 17.9% - worked in the human health and social work sector, the figures show.