Irish retailers have complained in recent months of strong competition from UK online retailers and Northern Irish rivals due to weakness in sterling following Britain's vote to leave the European Union.
Annual retail volumes grew 3.4 percent in December, down from 4.3 percent growth in November, to post the lowest annual growth since November 2013, provisional figures from the Central Statistics Office showed.
Sales fell 0.7 percent compared to November, or by 2.7 percent excluding car sales, which have had a strong year.
Provisional estimates for retail sales volume growth for 2016 were up 5.9 percent, or 4.3 percent if motor sales are excluded.
(Reporting by Conor Humphries; Editing by Jeremy Gaunt)
