Almost 90% of parents say they have had to cut back or delay spending in order to pay school voluntary contribution charges.
That's one of the findings of the Closing the Gap report, which was conducted by Grant Thornton on behalf of St. Vincent de Paul.
The research involved school principals and almost 1,500 parents.
It found that 86% say their children's schools ask for voluntary contributions - but 80% say it's not made clear that the contributions are optional.
The report found that the contributions range from 30 to 550 euro per child per year - with an average of 140 euro per child.
61% of parents say that they must also pay for classroom resources such as photocopying, printing and other materials.
One principal told the report that 'Voluntary contributions are a symptom of the underfunding of the education system' and are needed for the day-to-day running of the school.
The report also found that many parents spoke about the stress caused by requests for contributions, as well as the need to cut back on essential spending and getting into debt to pay the voluntary contribution, and feeling ashamed for struggling to meet the costs for their children.
