The number of new cars licensed in January increased by over 30% compared to the same time last year.
New figures from the Central Statistics Office show 13,624 private cars were registered last month - up from 10,469 in January 2010.
However the report shows that the number of commercial vehicles licensed fell by 4.6%, down from 1,016 in January of last year to 969 last month.
The CSO report shows that seven in every 10 new cars sold during January were diesel.
Toyota was the most popular make of car sold, followed by Ford, Volkswagen and Renault.