There was an 11% fall in new cars sold here during January in the worst start to the year for the industry for at least 25 years, according to the latest figures.
The Ford Fiesta was the most popular car with 195 sold and the small car enjoyed a comfortable margin over the next biggest seller, the Volkswagen Golf, which sold 150.
In fact, the Ford Fiesta was the most popular car in all the UK regions.
Meanwhile, the Ford Focus was the third-most popular here, with 139 sold.
The January sales were the lowest recorded since the Society of Motor Manufacturers and Traders (SMMT) started to release figures in 1996.
The SMMT said 5,030 new motors were driven off garage forecourts last month, compared to 5,660 in 2019.
Northern Ireland had the second steepest fall in car sales of the four UK regions, with Scotland reporting a more severe slump in sales of 18%. Car sales in Wales were down 2%, while sales in England fell by 6%.
Ulster Bank chief economist Richard Ramsey said: "January is traditionally one of the busiest months for new car sales in the calendar with March normally the top month.
"The 11% year-on-year fall in sales at the beginning of 2020 could well set the tone for the year ahead.
"Last month's sales volumes (5,030 vehicles) marked the fewest car sales for the month of January in at least 25 years and is a far cry (-38%) from January 2007's high of 8,154. 2014 was the last year local dealers posted an annual increase in new car sales. 2020 is not off to a good start".
The SMMT said that 149,279 vehicles left showrooms UK-wide, as confusion went on over diesel and clean air zones. Consumer and business confidence was also weak.
UK-wide, registrations of new cars by private buyers were down nearly 14% UK-wide, while fleet registrations had fallen 2.2%.
New diesel cars were down for the 34th month in a row, giving them just 19.8% of the market.
Demand for petrol cars also fell by 9.5% - though alternatively-fuelled cars had become more popular.
Hybrid electric cars (HEVs) increased by just over 20%, while demand for battery electric vehicles (BEV) more than doubled.
Combined, alternatively fuelled vehicle registrations made up 11.9% of the UK market as a whole in January - the highest on record, up from 6.8% in the same month last year.
The Government this week announced its ambition to end the sale of all vehicles with an internal combustion engine by 2035.
SMMT chief executive Mike Hawes said: "The new car market is a key driver of the UK's overall economy, so another month of decline is unsettling.
"Consumer confidence is not returning to the market and will not be helped by the Government's decision to add further confusion and instability by moving the goalposts on the end of sale of internal combustion engine cars."
He added the Government's blanket ban would not help short-term consumer confidence.