The Garda Bureau of Fraud Investigation has warned businesses of a recent scam "that has the potential to cause serious financial losses".
Up to 14 companies in Ireland have been defrauded out of €100,000 in a financial sting where they are asked to record new bank account details for clients.
"A number such bodies based around the country have received fraudulent instructions in the recent weeks via email or letter which instructed them to record new account details for their various clients," a Garda statement warned.
"There is no pattern in the fraudulent account details as they involve different financial institutions in both Ireland and the UK."
They are now asking all businesses to verbally confirm any instructions from customers requesting a change of account details.
According to gardaí, the scam has the potential to net the criminals more than €5m, but most of the money was either stopped from being sent or recovered due to the vigilance of the various financial institutions.
Gardaí have advised all businesses to conduct an immediate review of any instructions that they have received from customers involving a request for a change of account details.
As a security precaution it should be confirmed by verbal contact with the relevant financial control person in each business that purportedly sent change-of-account instructions as to whether they were genuine instructions or not.
Where any business suspects that such an attempt was made or indeed where they have received such a request they should immediately contact their local Garda station and their bank.