Revenue has seized more than 3.3 million cigarettes at Rosslare Europort in Co. Wexford.
The cigarettes were found when officers stopped a Polish registered truck which came on a ferry from France.
Officers found the cigarettes, with an estimated retail value of €2.4 million, within its load.
A man in his 40s is being questioned as part of the investigation.
This seizure was part of Revenue’s ongoing operations targeting the shadow economy and the supply and sale of illegal tobacco products.