The Central Statistics Office said exports were worth just over €7 billion in July, a drop of 10% compared with the same month last year. Imports remained little changed from a year earlier at just under €3.6 billion.
When adjusted for seasonal factors, exports in July were down 12% from June, while imports increased by 3%.
The CSO also released more detailed figures for the first half of this year, showing that exports rose by 7% from a year earlier to €47.1 billion. Exports of medical and pharmaceutical products grew by 14%, while chemicals exports were up 13%. Exports to the US increased by 14% to just over €1.3 billion.
Imports in the first half were up 9% compared with the same period last year to just under €25 billion. Petrol imports jumped by 24%.
Bloxham economist Alan McQuaid described the figures as "somewhat disappointing", though not surprising. "With signs that the global economy is slowing down, Ireland's export figures are likely to weaken in the coming months," he added.
NIB economist Ronnie O'Toole said the weakness came mainly from the pharmaceuticals and chemicals sectors, which are dominated by foreign multi-nationals. "While trade figures are very volatile and not too much should be read into one month's data, the export figures released today do reflect the weakness in Ireland's export markets," he said.
Davy economist Conall Mac Coille said monthly figures had been a "very poor" guide to final export figures in the national accounts. "Monthly movements in the trade balance are very erratic, so it is too early to discern any adverse impact on Irish export performance from weakening global demand conditions," he said.
