Gardaí and Customs officers in Co Cork have seized 80kg of what is described as high-quality cocaine, which they said has a potential street value in excess of €5m.
A consignment that arrived in Cork Port from Rotterdam in The Netherlands was taken to a premises in Bartlemy, Fermoy where the seizure took place.
A 56-year-old German national and a 45-year-old Irishman were arrested at the premises.
Another three people were arrested in follow-up searches; two of whom were Irish, aged 42 and 65, with the third man being a 46-year-old Hungarian national.
They are being held at a number of garda stations in Co Cork and Terenure and Crumlin in Dublin.
The find has been removed to a separate, secure location where an in-depth search is to be undertaken.
The drugs seizure comes as part of a joint operation between the Garda National Drugs Unit and Revenue's Customs Service with cooperation coming from Europol, Interpol and Dutch law enforcement agencies.