As many as 40,000 UK drivers based in the Republic risk driving illegally unless they transfer to an Irish licence before Brexit.
European Affairs Minister Helen McEntee, speaking at the National Driver Licence Service in Dublin, warned drivers who do not prepare risk prosecution.
“While a significant number of people from the UK or Northern Ireland have changed their driving licence, there are still an estimated 40,000 people living in Ireland on October 31, if in the event of a no deal Brexit, will be driving illegally,” she said.
The process takes about five to ten working days and costs €55.
The problem is that were the UK to leave without a deal, it becomes a third country and therefore such driving licences would no longer be recognised.
Those affected would have to apply again as if they are a new driver.
Ms McEntee also confirmed Taoiseach Leo Varadkar will meet British Prime Minister Boris Johnson tomorrow in New York.
In the wake of comments from EC President Jean Claude Juncker that checks will have to occur on the island of Ireland in the case of no deal, Ms McEntee denied the Government has misled the public.
For 18 months, the prospect of checks has been consistently denied by ministers until recently.
“Absolutely not, there has been no misleading. We have been very clear and very honest there would have to be checks in recent months,” she told the Irish Examiner.
"But they cannot be on the border, they cannot be a security threat. The Commission has been very clear.
"There cannot be a hard border and we cannot go back in history and allow history repeat itself."