Ireland’s industrial output fell 11.6% in October, according to data from Eurostat, the sector’s worst monthly performance since September 2012.
On an annual basis, industrial output here has fallen 7.5% since October 2012, according to the figures.
The sharp decline in Ireland's output compares with a 1.1% fall across the wider euro zone, highlighting the fragility of the bloc’s economic recovery.
The figure will come as a surprise to analysts, who had predicted a small month-on-month rise in output across the 17 countries.
The economic rebound of the €9.5 trillion economy almost came to a halt in the third quarter and the outlook remains clouded because of record high unemployment, weak consumer and business confidence.
The monthly fall was led by a 4% drop in the highly volatile energy production, followed by a 2.4% decline in production of durable goods, such as cars and electronics, and capital goods production was down by 1.3%.
Compared with the same period last year, industrial output in October rose 0.2% for a second month in a row.
In Germany, Europe's largest economy, industrial production fell 1.2% month-on-month, its biggest fall since July, while output in the second biggest economy - France - dropped by 0.3% for a second consecutive month.