New figures released to Labour's finance spokesperson Ged Nash in a parliamentary question show that about a quarter of PAYE workers are overpaying their income tax.
Mr Nash has called on all workers to make a tax return online and claim the tax reliefs they're entitled to.
"I secure this data every year so I can make a simple appeal to PAYE workers - do a tax return online and claim all of the tax reliefs and credits the law entitles you to claim, from tax relief on medical bills to the renters’ tax credit," said Deputy Nash.
"Every extra cent makes a difference to working families in the highest cost economy in the EU," he added.
Mr Nash said the figures issued from the Revenue Commissioners shows that around a quarter of all PAYE taxpayers in 2022 and 2023 may have overpaid tax.
"That’s a total of 245,000 in 2022 and 330,00 in 2023. The figures are remarkably similar from the corresponding data I received on the same date last year," he said.
"This leads me to believe that it may be some of the same taxpayers who year-on-year, fail to do a return and get the cash back that they are owed."
Mr Nash said average funds of around €735 could be due to PAYE workers who overpaid their taxes in 2022 alone.
"Based on figures issued on Budget Day in October 2023, the then Finance Minister said around €180 million could be due in refunds for the 2022 tax year, in total," he said.
"I have no doubt the pot of unclaimed money is similar for 2023," he added.
Claire Murphy, Tax Expert at Irish Tax Rebates said the deadline for Income Tax for self employed individuals is the 14th of November.
However, Revenue allows PAYE workers to access any returns for four years.
"So the deadline for any potential 2020 returns is the 31st of December 2024, and in January they will then be able to process any claims for 2024," she explained.
"People should make sure that they have claimed their working from home expenses from 2020, if they worked from home during the pandemic, and also their medical expenses for 2020 as they are due to miss out on these claims shortly," she added.
In addition to the above credits, Ms Murphy said workers could also be missing our on flat rate expenses from 2020 that they would be due from their occupation - for example nurses, teachers or construction workers.
