New figures from the Central Statistics Office show that monthly wholesale prices, or factory gate prices, fell by 2.4% in May compared to a rise of 0.1% in May of last year.
On an annual basis, factory gate prices rose by 6.3% in May compared to a rise of 9% in the year to April.
Today's figures show that the most significant changes were seen in the prices of dairy products, which rose by 0.7%, while meat and meat products were up 0.3%.
There were also falls in the prices of basic pharmaceutical products and pharmaceutical preparations (down 3.7%).
Computer, electronic and optical products fell by 3.6% while other food products - including bread and confectionery - were down 2.6%.
The CSO also noted that all building and construction materials increased by 1.6% in the year since May of last year, with the biggest increases in hardwood (up 12.3%) and glass (up 6.4%)
