Parents of children starting secondary school this September will have to pay up to €1,200 on books, uniforms and other additional costs, the Labour Party has claimed.
Education spokeswoman Jan O'Sullivan said the supports provided by the Government were inadequate and left many families on low incomes struggling to prepare their children for school.
"We talk about free education in Ireland but in fact it's a myth - when you see the kind of money parents have to come up with and the effect it has on relationships within families," she said.
"Considering how much money we have in the economy, it's an absolute shame the Government hasn't increased the supports."
Ms O'Sullivan called on the Government to increase the income limits for the Back to School Clothing and Footwear Allowance to match limits for the Family Income Supplement, and called on it to increase the allowances to €180 for primary school children and €250 for secondary school students.
She also said the Government should provide a special grant of €400 for children who qualify for assistance when they start secondary school, in recognition of the high cost of starting second-level education.
Labour Party TD for Cork North Central Kathleen Lynch said a failure by the Government to review the level of payments meant effectively that only those families on social welfare qualified for grants.
According to the Labour Party's Back to School report, launched yesterday, kitting out a primary school child in a uniform can cost more than €300, while a secondary school student's clothing can cost more than €400.
Textbooks are another major cost, with parents having to pay around €95 for primary school books and €420 for the first year of secondary school, as well as spending cash on stationery, the report found.
In addition, there were administrative costs for sports and other extra-curricular activities as well as school meals.
The Labour Party also criticised the practice of "voluntary contributions", which average around €70 for primary school pupils and €120 in secondary schools, and which are used to supplement a school's income.
Ms O'Sullivan said parents felt under moral pressure to pay the contributions, and demanded that the Department of Education provide sufficient funding to cover school budgets.