Almost 59,000 new cars were licensed in the first five months of the year, according to the Central Statistics Office, a 27.4% rise on the same period of last year.
More than 7,600 of those were licensed last month- 9.5% higher than in May 2013.
The number of used cars imported into the country between January and May was also significantly higher - up 18.4% at almost 23,100.
Meanwhile, more than 7,600 new goods vehicles were licensed in the year to May - up more than 43% on the same period of 2013.
The number of new tractors licensed also increased during the period, up 23% to 1,154.
According to the CSO, Volkswagen was the most popular brand in the first five months of the year, representing almost 12% of all vehicles licensed in the period.
Toyota vehicles represented 11% of all those licensed, while Ford represented almost 10%.
The CSO's licensing figures relate to the first issuance of a motor tax disc for a new or newly imported vehicle.