Revenue officers seized 300,000 Minsk branded cigarettes on Tuesday with an estimated retail value of €210,000, and representing a potential loss to the exchequer of approximately €167,000.
A separate seizure on Monday involved 160,000 cigarettes branded NZ Gold. They had an estimated retail value of over €113,000, representing a potential loss to the exchequer of approximately €89,000.
In a statement, Revenue said both operations were carried out as a result of routine profiling and in both cases the illegal cigarettes were discovered with the assistance of a mobile X-ray scanner.
They were concealed in containers that had arrived into Dublin Port from Rotterdam in the Netherlands.
Investigations are ongoing.