The National Consumer Agency has urged U2 fans to contact gardaí if they bought tickets for a Slane concert that was never scheduled to take place.
The Garda Bureau of Fraud Investigation and Interpol are already investigating the website globalticketshop.com, which advertised for a U2 Slane concert on July 1st and 25 dates in other European countries over the summer.
The website has since taken down the dates after being contacted by both the owner of Slane Castle Lord Henry Mountcharles and by Live Nation, U2's promoters.
The band also issued a statement on its website urging fans not to buy tickets from unauthorised websites. "Please don't get stung buying tickets for shows that don't exist," the band said.
The NCA said fans who had bought tickets for a Slane concert should contact the Garda Bureau of Fraud Investigation with the details.
They should also seek a refund from their credit card company if they paid by credit card.
John Shine of the NCA said fans should always exercise caution in buying tickets especially from new or unknown websites.
He also advised that they cross-reference with the band's own website to make sure the concert is genuine.