Investigations are ongoing after Revenue officers seized 26,000 cigarettes in separate operations in Cork and Dublin last Friday.
As a result of a targeted operation, Revenue officers seized 10,000 cigarettes at Horgan’s Quay.
In a statement, Revenue said that the smuggled cigarettes were discovered onboard a cargo vessel registered in Antigua and Barbuda.
The 'Winston' and 'ASSOS' branded cigarettes have an estimated retail value of over €6,700, representing a potential loss to the exchequer of €5,320.
Separately, on Friday as a result of routine profiling, Revenue officers seized 16,000 cigarettes at Dublin Airport.
The smuggled cigarettes were discovered in the baggage of two Polish nationals who had disembarked a flight from Poznan, Poland.
The smuggled cigarettes, branded 'L&B' have an estimated retail value of over €10,000, representing a potential loss to the exchequer of €8,500.
Revenue says the seizures are "part of Revenue’s ongoing operations targeting the shadow economy and the supply and sale of illegal tobacco products".
"If businesses or members of the public have any information regarding the smuggling they can contact Revenue in confidence on free phone number 1800 295 295," they added.