New car sales were down 22.5% in May when compared to the same period last year, according to figures from the Society of the Irish Motor Industry.
Just over 51,500 new cars have been sold so far this year, 14.5% lower than the number of sales in the first five months of 2012.
SIMI’s director general Alan Nolan said it had been a very poor year to date for the industry, with the May figures continuing a negative trend.
However Mr Nolan said the arrival of the ‘132’ registration plate in July creates the potential for increased activity in the second half of the year, when sales would have traditionally fallen further.
According to the SIMI figures, Toyota was the most popular make of car in May while Volkswagen remains the most popular brand for the year so far.
The Nissan Qashqai was the most popular model last month, while the Volkswagen Golf is the most popular car of 2013 so far.
Almost 60% of cars sold in the year to date fall into the lowest CO2 emissions band, while a further 34% are in the second lowest category.
Almost 73% of new cars sold this year have been diesel models, while just 0.04% of those sold have been electric.