GARDAI are warning traders and the public to be vigilant after the discovery of several thousand pounds worth of good-quality counterfeit bank notes in £5, £10 and £20 denominations.
Gardai are concerned because the fake notes are not detectable by ultra-violet security lamps which are widely relied on by businesses to detect counterfeit currency. The notes, which have been detected in the past week, have been passed off as genuine in businesses throughout the State.
A spokesman for the Garda Bureau of Fraud Investigation said the quality of the batch of notes showed a "concerted" counterfeit effort, the scale of which has yet to be established.
When the fake notes are held under the ultra-violet security lamps, they react in the same way as genuine bank notes by becoming dull in some areas and fluorescent in others.
"It's vitally important that people whose job is handling money are not relying on an ultraviolet light as a security check. It's not adequate at all to examine this series of counterfeits," said the spokesman.
The counterfeit notes differ from genuine notes in several ways. The watermark on the fake £10 and £20 notes is stamped on the back and can be seen without holding it up to the light.
When held up to the light, the watermark is barely discernible. The counterfeit £5 notes have no watermark at all. On genuine notes, the watermark is incorporated during manufacture and is always apparent and distinctive when held to the light.
The vertical silver windowed security thread in real notes is exposed in parts along the note, and when the note is held up to the light, the thread appears as a continuous line.
On the fake notes, the silver line is made of paint rather than nylon thread and when held up to the light it appears as a broken line.
Gardai are advising workers in shops, businesses, pubs and banks to examine carefully all notes for these features, rather than relying on the ultra-violet security lamps.
Any counterfeit notes should be handed over to the Garda Bureau of Fraud Investigation or local gardai. Gardai are also appealing for anyone with information about the distribution or passing of the counterfeit notes to contact them.