New figures from the Central Statistics Office show that the volume of retail sales fell by 0.6% in April on a monthly basis as new car sales slowed.
On a yearly basis, the volume of retail sales rose by 1.6% - the slowest pace of growth in almost four years.
Consumers are importing more used cars due to the sharp fall in the value of sterling against the euro since Britain's vote to leave the European Union.
The CSO said that when car sales are excluded, the volume of retail sales rose by 0.4% on a monthly basis and by 6.4% on an annual basis.
Car sales fell by 1.7% in April compared to March, while sales of books, newspapers and stationery decreased by 1.2%.
The sectors with the biggest increase in the volume of sales were department stores - with sales jumping 8.3%. Furniture and lighting sales rose by 3.9% while bar sales were also 1.6% higher.
Commenting on today's figures, Merrion economist Alan McQuaid said that while retail sales continue to remain erratic on a monthly basis and are still swinging back and forth, the underlying trend is positive.
"While most attention has been on robust car sales in the past couple of years, personal spending in other areas has generally picked up too over the same period and is becoming more broad-based," the economist said.
Mr McQuaid said the Brexit fall-out and the uncertain economic implications will likely continue to impact on Irish consumer sentiment, and in turn personal spending in the months ahead.
He said that personal spending growth is expected to be positive again in 2017, boosted by a further fall in unemployment, but with the increase in headline sales likely to be lower than last year.
"The early indications are that new car sales this year will be down on 2016, but other areas of expenditure will pick up. Indeed, excluding motor trades, a higher retail sales rise than 2016 is anticipated," he added.
Goodbody's chief economist Dermot O'Leary noted that car sales had been heavily influenced by cheaper used car imports from the UK due to weaker sterling, which grew by 56% on an annual basis in the first quarter of the year.
"The weakness in new car sales, therefore, cannot be taken as an indication of consumer caution," he stated.
