The Revenue Commissioners has begun a public awareness campaign to highlight unclaimed tax reliefs.
Credits can be claimed from a range of services including bin charges, medical expenses, union subscriptions and nursing home charges.
"There's a range of entitlements that taxpayers are entitled to and we feel there are a large number of taxpayers out there who have not claimed their full entitlements," said Revenue Commissioners spokesman John Leamy.
"The purpose of this campaign is to highlight to people the reliefs and credits that are out there for people so they can claim back the tax they are owed."