Dye-stained banknotes stolen during cash-in-transit robberies have been turning up in self-service check-outs, ticket machines and even banks, gardai have revealed.
Up to two million euro taken in raids in recent years could be in circulation, with officers appealing to the public not to accept them as legal tender.
Assistant Garda commissioner Derek Byrne launched a new awareness campaign warning consumers and retailers that a dye-stained note is probably stolen and is being laundered.
"We have to block the criminal and close down any avenue they have for exchanging bank stained notes," he said.
"It is vitally important that we work together and take whatever steps necessary to make it as difficult as possible for criminals to profit from their often violent, illegal activity."
Notes stolen during cash-in-transit robberies are damaged when a dye explodes as the cash box is opened without the correct codes.
A new website - www.banknotewatch.ie - shows what a dyed note looks like and outlines how to exchange a stained note for a new one, which can take up to two weeks.
However gardai warned people handing in notes will be questioned over where they came from.
"If you have a suspicion around a note, report it. Don't be involved with the processing or distributing of it," Mr Byrne continued.
"The idea would be the innocent community would not be at any loss. There is a way of redeeming the money. Don't accept this money. Don't give the criminals an outlet."