Gardaí believe they have uncovered a sophisticated operation to make counterfeit money in Co Laois.
Four men in their 40s and 50s have been arrested; two are being detained in Tullamore and two in Portlaoise Garda Station.
The discovery was made this morning and gardaí said it will take a number of days before they can establish what is on the site.
A number of buildings at a site near Borris-in-Ossory have been sealed-off for a technical examination by a forensic investigation team.
Gardaí said they arrested four men for suspected offences under the Theft and Fraud Offences Act 2001 as part of a major investigation into the counterfeiting of money.
They say the operation was initiated following an analysis of increased activity in counterfeiting across Europe.
