Consumer price growth in the EU which expanded to 20 nations when Croatia joined on 1 January, slowed to 9.2% in December from 10.1% a month earlier.
This was below forecasts of 9.7% in a Reuters poll, data from Eurostat showed.
But this seemingly good news masked a more malignant trend as the biggest chunk of the decline came from lower energy prices while all key components of core inflation accelerated.
Eurostat figures show that when measured by the Harmonised Index of Consumer Prices, Ireland's inflation rate is estimated to come at 8.2% in December, down from 9% in November.
