All three arrests were made in Laois.
Three men have been arrested in the Portarlington area of Laois following a number of searches in the area on Wednesday.
Gardaí conducted the searches as part of an investigation into organised crime, drugs and firearms trafficking across the Midlands area.
The operation was led by the Laois Detective Unit and Laois Drugs Unit supported by the Armed Support Unit, Air Support Unit, Garda Dog Unit, uniformed members from the Laois/Offaly Division, Customs and Revenue and the Laois Dog Warden.
The men were arrested under Section 30 Offences Against the State Act and are being detained at Portlaoise, Tullamore and Birr Garda Stations.