11 men were arrested in the plant, which included a living quarters.
In a joint operation, Revenue and An Garda Síochána have closed down an illicit commercial cigarette factory in Jenkinstown, Co. Louth.
Part of the Joint Agency Task Force, the operation took place before 8am on Thursday, 15 March.
According to Revenue, this was the first time a commercial illicit cigarette production plant was discovered in the State and the factory was in full operation when Revenue officers and the Armed Support unit entered the premises.
In total, 11 Eastern European men, aged between their late 20s and 50s were arrested and brought to Dundalk Garda Station, where they have been detained under Section 4 of the Criminal Justice Act 1984.
Revenue officers found over 40 tonnes of tobacco, all the pre-cursor components for the manufacture of cigarettes, and approximately 25 million cigarettes, which were branded 'Mayfair' and ready for distribution.
Revenue has described the plant as a "sophistic self-contained operation" with machinery that is capable of producing 250,000 cigarettes per hour along with living quarters, as well as pre-processing, processing and packaging facilities.
The illicit cigarettes that originate in the factory have previously been seized in both Ireland and the UK.
It was also noted that if the finished cigarettes had reached the Irish market, the estimated loss to the Exchequer would have been approximately €12 million.
