It is unclear why sales dropped - Brexit and a dip in economic sentiment have been cited as possible causes...
New figures show a major fall-off in new car sales during October. Year-on-year new registrations fell by 12% - or 316 units.
The month brought the total number of new cars sold so far in 2016 to 145,433 - that's 18% higher than the same time last year.
The five top selling manufactures so far in 2016 are - starting with the highest-selling - Hyundai, Volkswagen, Toyota, Ford and Nissan.
While the top selling models in 2016 so far rank as:
1. Hyundai Tucson
2. Volkswagen Golf
3. Ford Focus
4. Skoda Octavia
5. Nissan Qashqai
Commenting on the figures SIMI Director General Alan Nolan said: "In the final quarter of the year we do expect to see a slow-down in new vehicle registrations, with much smaller numbers each month compared to the peak selling months; indeed the Industry is already moving its focus to the 2017 sales period, as can be seen and heard in current advertising campaigns.
"Whether this has been influenced by the Brexit situation or just a slowing of retail activity in the Irish economy, after a sustained period of growth, is not yet clear but this is something that the Industry will be continuing to watch closely," he added.