Revenue has seized over nine million cigarettes - with a retail value of 4.5 million euro - at Dublin Port.
The container left China and sailed via the ports of Ningbo and Rotterdam before arriving in Dublin.
The 'Dorchester' brand cigarettes were described as 'vacuum cleaners' and are believed to be counterfeit.
In a separate operation in the North five men have been arrested after 4 million cigarettes were found in Tyrone.
A suspected mobile fuel laundering plant was also seized.