More than 11,700 new, private cars were licensed last month, according to the Central Statistics Office, a rise of almost 45% on figures from April 2013.
There was also an increase in the number of imported cars licensed during the month, up 8.8% to 4,783.
The figures meant that more than 51,000 new cars have been licensed in the first four months of 2014 – a 30.7% increase on the same period of last year.
Meanwhile, more than 18,000 imported cars have been licensed in the year-to-date, up 21.8% on the first four months of 2013.
The vast majority (74.2%) of the new cars licensed last month were diesel models, with almost all others being fuelled by petrol.
Volkswagen was the best-selling car brand during the month, according to the CSO, with 1,542 cars licensed. Nissan was second with 1,183, while 1,051 Toyota cars were also sold during April.