Inland Revenue (IR) is warning people to be wary of hoax emails.
The deceptions involve asking people to ring a phone number to confirm their billing address.
Other emails claim to offer tax refunds, with a link to a fake website with an IR logo. People are asked to enter personal details, including user names and credit-card details.
Anyone who provides information risks having their details stolen.
“Our advice is to never click on any links within a suspicious email, do not reply to the email and delete it,” says IR spokeswoman Heather Daly.
People who have replied to the emails should contact their bank or credit-card provider.
If they have entered their bank details, they should change their passwords.