More than €2m in counterfeit notes have been seized by gardaí investigating the activities of dissident republicans.
Gardaí have described the counterfeiting operation as "highly sophisticated".
The notes, which are all in €50 denominations, are said to be of very high quality and gardaí believe some of them are already in circulation.
They have issued a warning to traders, members of the public and business people to be very cautious when handling €50 notes.
A specialised Heidelberg industrial printing press has also been seized.
Three men have already been charged and brought before the courts.
The garda investigation is continuing.