New car registrations were up by 7.4% in September when compared to the same month last year.
However, the latest figures from the Society of the Irish Motor Industry (SIMI) show since the start of the year they are down 7.5% compared to last year.
There was a 20% increase in the number of imported used cars in September, and a 6.7% increase in the year to date.
2,976 new electric vehicles have been registered so far this year.
"With the announcement of Budget 2020 only a week away, we in SIMI continue to underline to Government not to increase taxation on new cars," said SIMI Director General Brian Cooke in a statement.
"New car sales have fallen in each of the last three years, and with Brexit now only weeks away, business risk in our sector is at its highest level in almost a decade.
"In this uncertain business and consumer environment, any taxation increase would only further undermine an already fragile new car market.
"This in turn will endanger both Exchequer revenues and employment, while at the same time act as a barrier to the renewal of Ireland’s car fleet which is key to reducing emissions from transport.
"Our industry can’t afford for the Government to get Budget 2020 wrong, as the impact would have far-reaching consequences that could extend for many years well beyond 2020."