New figures from the Central Statistics Office show that industrial production levels fell by 2.5% in May from the previous month.
But on an annual basis, production in May jumped by 32.3% compared to the same month last year.
The CSO said that the modern sector - which is made up of high technology and chemical sectors - slowed by 0.7% in May. There was also a decline of 0.8% in the traditional sector.
Today's figures show that the seasonally adjusted volume of industrial production for the three months from March to May was 17.9% higher than in the preceding three months.
Commenting on today's figures, Davy economist Conall Mac Coille said they show that the pharmaceutical sector appears to be bouncing back, with output continuing to recover in indigenous domestic companies.
The economist said the "spectacular" 32.3% growth in manufacturing output in the year to May probably overstates the true improvement in conditions, reflecting volatility and highlighting the risk of further revisions going forward.
He also pointed out that today’s data were the first to incorporate methodological changes and reweighting of sectors, which will raise the probability of future revisions.