Also, according to figures released by the Society of the Irish Motor Industry, sales in March were down by 10.5pc against the same moth last year.
SIMI says March was a 'challenging' trading month with tje combined effects of snow days and two public holidays in the same month.
SIMI director general Alan Nolan says the Brexit effect remains 'dominant' with used car imports up 9.5pc for the quarter.
Light commercial vehicles sales showed a continuing increase, currently up 5.4pc in the year to date.
In cars, Volkswagen, Toyota and Hyundai were the biggest selling brands for the quarter.
The top model is the Nissan Qashqai, followed by Hyundai's Tucson and Volkswagen's Golf.
The diesel engine share has reduced from 67pc this time last year to 56pc.
The number of passenger cars registered so far in 2018 is 71,842. LCV registrations are 12,537.