People living in Northern Ireland who cross the border without a reasonable excuse face a €100 fine from today.
The new measures apply to anyone who is "not ordinarily resident" in the Republic of Ireland and came into force from 7am this morning.
The Gardai said, if enforcement is required, a fixed payment notice for €100 will be issued to each person who is in breach of the regulation.
Several checkpoints have set up across Co Donegal today; and our reporter Barry Whyte has been getting reaction from people living in the Lifford and Strabane area....