Gardaí in Co Westmeath are questioning a man in his 20s following the seizure of an undisclosed quantity of cigarettes near Mullingar yesterday.
The cigarettes were found when officers stopped and searched a van on the N4 just after 5.30pm.
Investigations are being carried out to determine if the cigarettes are counterfeit.
Gardaí say they had an estimated value of around €100,000.