The motor industry has called on the Government not to increase tax on new cars in next month's Budget.
The call from the Society of the Irish Motor Industry comes as the latest figures show that new car sales slowed again in August.
SIMI said that total new car registrations for August fell by 13.3% compared to the same time last year.
New car registrations year to date slowed by 7.9% to 110,572 on the same period last year when a total of 120,003 new cars were registered, SIMI added.
Meanwhile, registrations of imported or used cars in August increased by 10.2%, while year to date imports are up 5% compared to 2018 figures.
SIMI also noted that new Light Commercial Vehicle (LCV) registrations are up over 35% in August compared to the same month last year, but registrations year to date are down 2.2%.
Registrations of new Heavy Commercial Vehicles (HGV) slowed by 20.7% from August 2018, but so far this year they are up 3.1%.
Brian Cooke, SIMI Director General, said that despite the strong economic growth, the new car market continues to contract this year, with registrations for the month of August following this trend.
"In this business context and with the increasing likelihood of a hard Brexit, SIMI is calling on the Minister for Finance not to increase taxes on new cars in Budget 2020," Mr Cooke said.
Mr Cooke said it is important that the new car market is as strong as possible from both an environmental and employment view point.
"Instead the current Brexit and taxation mix only encourages people to hold on to their older higher emitting cars for longer. New car sales need to increase if Ireland is to see the real benefit of improvements in emissions from new technologies, and taxation systems should support not hinder this," he added.
SIMI figures today also reveal that the top five selling car brands so far this year are Volkswagen, Toyota, Hyundai, Ford and Skoda.
The top selling car in August was the Hyundai Tucson, SIMI added.
The five top car models registered so far this year are the Toyota Corolla, the Hyundai Tucson, the Nissan Qashqai, the Skoda Octavia and the Volkswagen Tiguan.