New figures from the Central Statistics Office show that the number of new private cars licensed in August decreased by 6.2% to 7,202.
Some of that sales dip can be attributed to a more cautious consumer, while some car buyers are also opting to save money by buying on the other side of the border.
Today's CSO figures also reveal that the total number of used or imported cars licensed rose by 8.5% to 9,320 last month.
In the first eight months of this year, a total of 103,582 new private cars were licensed - down 7.1% compared with the same period last year.
The CSO also said that the number of used private cars licensed in the first eight months of the year rose by 4.7% compared with the same time last year.
Meanwhile, there was a 9.7% increase in the number of new goods vehicles licensed in August, bringing the total to 2,499.
Today's figures also show that Volkswagen was the most popular make of new private cars licensed in August. It was followed by Toyota, Hyundai, Ford and Skoda.
The CSO noted that together these five makes represent 47.6% of all new private cars licensed last month.
The figures also revealed that the number of electric and hybrid vehicles accounted for 10.6% of all private cars licensed in the first eight months of 2019, up from 6.7% with the same time last year.
And diesel vehicles accounted for 46.6% of all new private cars licensed so far this year, compared with 54% last year.
Licensing and registration of cars are different processes. A vehicle is licensed when a valid motor tax disc is issued for the first time whiles registration occurs when a vehicle gets its licence plate for the first time.