Revenue officers seized 2.9 million smuggled cigarettes during a search in Co Kildare on Wednesday.
This was carried out under warrant on a premises in Newhall.
The cigarettes, branded 'NZ', originated in Belarus and have a retail value of over €1.6m.
This represents a potential loss to the exchequer of over €1.3m, Revenue said.
The seizure was made during an operation conducted as part of the Cross-Border Joint Agency Task Force.
A man aged in his 60s was questioned and investigations are ongoing with a view to prosecution.
Separately on Thursday, Revenue officers in an intelligence-led operation seized approximately 500 grams of herbal cannabis - with an estimated street value of €10,000 - during a search of a house in Coolock, north Dublin.
This operation was conducted by Revenue's Customs Service, Gardaí from the Divisional Drugs Unit in Coolock Garda Station, and the Drugs and Organised Crime Bureau.
A 22-year-old man was arrested by Gardaí and is being held at Lucan Garda Station under Section 2 of the Criminal Justice Act.
Main image: File photo shows a previous seizure of 'NZ' branded cigarettes