Gardaí are warning about a rise in online scams.
They say cybercriminals are also targeting people in more sophisticated ways, which makes the scams harder for people to spot.
A conference is being held in Dublin today to warn businesses about the dangers.
Detective Chief Superintendent Patrick Lordan says it is an issue that affects everyone.
"Whether you're a builder or whether you're a farmer, whether you're a businessman or a banker, they all look like a very convincing email that you'll get in from your supplier or clients," he said.
"It will ask you to change bank account details in a lot of the cases and once you change those bank account details and the next invoice comes in from that supplier or client, it goes to the wrong account.