The AA has warned that British drivers based in Ireland may not be able to take to the roads in the event of a no-deal Brexit.
In a blog post, the association says while "it is very unlikely to come to that", plans are in place.
It says: "Recent reports have highlighted that British licence holders resident in Ireland who have failed to previously exchange their licence for an Irish licence must do so in advance of March 29th in order to continue driving legally in the event of a no-deal Brexit."
It says on March 30th, in the event of a no-deal Brexit, British licences will not be valid for people who are an Irish resident.
But it adds that an emergency change to the law can be prepared and ready to go.
The AA also says it has been pursuing this and that "plans are in hand."
"It would need an emergency 'patch' in legal regulations to recognise them, but the Department (of Transport) is aware of the issue and the AA has discussed it with them."
The AA explains: "Brexit or no Brexit, you are supposed to swap your British licence for an Irish one if you are resident in Ireland for more than 100 days.
"That law has never been enforced and didn't matter while both licences were European."
It says those who have applied to change their licence from British to Irish should see it processed with no problem.
It takes between 10 and 17 days to process, but the current situation may lead to increased demand.
For Irish residents who hold a British licence after March 29th "the way in which you exchange that for an Irish licence will depend on new post-Brexit regulations. They are not yet clear", the AA adds.
However motor insurance remains valid all the way through.
For those who have an Irish licence and are travelling in Britain or Northern Ireland, there is no issue. The UK already legally recognises EU licences.
While those who have an Irish motor insurance policy and are driving in Britain or Northern Ireland may need a 'Green Card' declaration of their insurance cover.