PAYE taxpayers could be paying up to €350 million more to the Exchequer than they should each year according to an Oireachtas inquiry published today.
"The Revenue is proficient in the area of tax collection, as indeed they should be. However, Revenue has an equal duty to demonstrate the same proficiency to people who overpay tax," the report from the Oireachtas Finance and Public Service committee found.
The report found that hundreds of millions of euros in allowances from trades' union fees, medical expenses and train tickets were unclaimed annually because taxpayers are not aware of their entitlements. Only half of trade union members claim their union dues.
Chairman of the committee, Fianna Fail TD Sean Fleming said the rule that a taxpayer can only claim back expenses from the last four years should be scrapped.
"It was brought it as a matter of administrative inconvenience, and I have no doubt that it is convenient for the Revenue, but they should be required to repay overpayments for all years, not just four years, if overpayments have been made," he said.
The committee's report also found that the language used in Revenue publications was hard to interpret, although they accept that many taxpayers are wary of approaching them.
In response to the report the Revenue Commissioners said "nobody should doubt Revenue's commitment to doing as much as possible to assist and encourage the public to claim all of the tax credits and reliefs that are due to them."
Fine Gael deputy leader Richard Bruton said: "It is important that Revenue inform taxpayers about reliefs with the same enthusiasm that they go out and collect taxes."
The committee heard public hearings earlier this year which included presentations from the Revenue Commissioners, Irish Taxation Institute and the Consumer Association of Ireland.
Labour TD Joan Burton added; "The Revenue has come a long way to reform the way it works, but there is still a distance to go."