Cannabis with an estimated street value of 1.8 million euro has been seized by gardai.
Three men were arrested when officers searched a van and a car in Castlewarden, Co Kildare, and discovered 600,000 euro of drugs.
In a follow up search of a business premises in the Cookstown area of Tallaght, another 1.2 million euro of cannabis herb was found.
The three men, who are aged 31, 40 and 50, are being questioned under the provisions of Section Two of the Criminal Justice (Drug Trafficking) Act 1996 at Clondalkin Garda Station.
The operation was carried out by the Garda National Drugs Unit, with officers from the Organised Crime Unit.