Official figures show that the number of new cars licensed in July fell by 73% compared with the same month last year.
The Central Statistics Office said there were 4,355 new cars licensed in July, which is down from 16,175 a year earlier.
For the first seven months of this year, new car figures are showing a drop of 64% to 46,270.
The figures are broadly in line with those from the industry released earlier this month, which showed a 77% annual fall in July.
At that time, the Society of the Irish Motor Industry said the drop was not as dramatic as it might appear, as there was an unusual increase in July last year.
Many people are believed to have held off buying new cars last year until the introduction of a new car tax system.
