Cigarettes worth over €4.5m to the exchequer have been seized by Revenue in Dublin Port.
Nine million 'Dorchester' brand cigarettes described as 'vacuum cleaners' were seized during the search of a container from China.
Meanwhile, in a separate operation five men were arrested and more than four million cigarettes along with a suspected mobile fuel laundering plant were seized in Co. Tyrone.
Benny Gilsenan from Retailers against Smuggling has said that the criminals involved are very organised and will not be affected by today's haul.
"You have to compliment the customs on their work, but unfortunately they seem to be getting a very small amount of what is coming in," said Mr Gilsenan.
"They are obviously so well organised that the nine million that they loose are bringing in another four or five similar amounts to cover the losses."