Officers from Revenue's Custom Service have seized 3.8m cigarettes in Wexford.
The cigarettes are said to have an estimated retail value of €1.5m with a potential loss to the Exchequer of €1.3m.
The "821 Red" brand cigarettes arrived into Dublin Port from Rotterdam in a maritime container and were subsequently seized in Enniscorthy in a Customs operation.
Two men were interviewed and investigations are ongoing both nationally and internationally.
A spokesperson for Revenue said this is not the biggest seizure of cigarettes this year.
Seven million cigarettes were seized in July and 5.3m in May.
In a separate operation yesterday afternoon, 12,000 "West" brand cigarettes were seized at Dublin Airport and a 53-year-old Polish man was arrested.
He appeared this morning in the Court of Criminal Justice and was remanded in custody, by Judge Denis McLoughlin, to appear at Clover Hill on 26 September.
These seizures are part of Revenue's ongoing operations targeting the smuggling and sale of illegal cigarettes.
