The volume of retail sales fell by 0.6% in January on a monthly basis, while there was an annual increase of 1.3% - the lowest annual growth in nine months.
New figures from the Central Statistics Office show that if car sales are excluded, retail sales rose by 1.1% in January from December, while there was an increase of 5.7% on a yearly basis.
Today's figures show that retail sales in department stores fell by 4.2% in January on a monthly basis, while motor sales fell 0.9%.
But January also saw increases in sales of pharmaceuticals, medical and cosmetic articles while other retail sales - which include the likes of carpets, music and video recordings, games, toys and flowers - jumped 18.4%.
Commenting on today's CSO figures, Merrion economist Alan McQuaid said that even with the fluctuation in consumer sentiment, overall personal spending has been positive in the past couple of years.
He said that consumer spending has been boosted by the increase in the numbers employed in the country, despite the fact that the weakness in sterling since the Brexit referendum has enticed some shoppers to spend in Northern Ireland.
"Looking ahead to 2018, we think personal spending will post another positive increase as the unemployment rate drops below 6% and disposable incomes rise, though the increase in headline retail sales is likely to be lower than 2017, at around 2%," the economist added.
