Fraudsters have accessed the personal details of thousands of taxpayers held on a Revenue website.
Revenue has written to 3,000 taxpayers telling them that personal details held in the user profile of their Revenue myAccount are likely to have been accessed by the fraudsters.
The scam is due to those who were affected having inadvertently provided their personal details to the fraudsters.
A text message that taxpayers thought was from Revenue prompted them to give their personal security details and their date of birth to the fraudsters.
Tax officials said they regularly remind taxpayers that Revenue never sends text messages requiring the provision of personal information via links, pop-up windows, reply text or email.
"Following an investigation by Revenue's IT department into this latest scam, we are contacting approximately 3,000 taxpayers to make them aware of our concerns that their personal details may have been accessed, the possible serious implications for them and to set out some practical things they can do to minimise the extent of any fraud perpetrated against them," said Revenue's chief information officer John Barron.
Mr Barron said that the security of Revenue's systems has not been compromised in any way.
"However, the nature of this particular type of scam has led to some taxpayers unwittingly compromising the security of their personal myAccount profile details by providing information such as their PPSN (personal public service number), date of birth and myAccount password to fraudsters."
The scam occurred after the taxpayers had clicked on a link, within a text that was sent to them by the fraudsters, which purported to be the Revenue myAccount log-in screen.
If the details provided after clicking the link are valid, the fraudsters then use these details, that have been provided by the taxpayer, to access the taxpayer's myAccount user-profile screen.
The scammers may then be able to obtain further information, potentially including bank details where the taxpayer has recorded these with Revenue, the tax authority has warned.
Mr Barron said that the letter notifies the taxpayers that Revenue has temporarily deactivated their myAccount access.
The letter also advises the taxpayers of the important next steps that they should follow.