It is claimed the spiralling cost of transition year is leaving some parents in financial difficulties.
The Society of Saint Vincent De Paul says some schools are asking for up to €900 to cover the costs of extra activities in transition year.
The charity's fielded over 6,000 calls in recent months from parents who are struggling to pay back to school costs.
SVP spokesperson Caroline Fahey says so-called 'voluntary contributions' for transition year should be phased out.
"In the more affluent schools, there might be better opportunities for the students to take part in different activities, different volunteering, things like that, whereas when the parents don't have the money maybe the activities are a bit more curtailed for the students," she said.
"It really is a pity to limit the opportunities for young people at this early stage.