There have been arguments that imposing higher pupil-teacher ratios (PTRs) on fee-paying schools has a deeper impact on the 20 Protestant schools that charge fees.
It is claimed they do not all have large wealth and the danger of some being forced to close would leave their students with no access to a school of their ethos.
But the department’s report found no evidence that Protestant schools should be exempted from any increases in PTRs being applied to fee-charging schools.
The report said similar proportions of Protestant and other fee-paying schools would lose over 30% of their discretionary funding if the PTR funded by taxpayers was increased from 21:1 to 28:1.
However, similar numbers would also still have very high funding available to supplement what they receive from the department.
Paul Colton, Church of Ireland Bishop of Cork, Cloyne, and Ross tweeted that not all fee-charging schools are bastions of privilege, and they are the only option for many children of minority faiths.
The report showed fee- paying schools have over €81m between them — almost €1.5m each on average — above what similar-sized free schools would have, after lost grants, less favourable teacher funding, and other costs are taken into account.
But there are wide variations in the additional funding, which ranges from €112,000 to €4.7m.
Labour Party Dublin South West TD Eamonn Maloney said the figures raise questions about the continued payment of teacher salaries and other costs totalling about €100m a year.
“Working-class children can never avail of the many advantages of attending a private school, not because they lack brains but because their families are not sufficiently well off,” he said.
His views reflect those of many of Education Minister Ruairi Quinn’s Labour Party backbenchers, as well as the Teachers’ Union of Ireland.
But the Joint Managerial Body, whose 370 religious- run member schools include most in the fee-paying sector, said parents have a choice if they wish to spend extra money on their children’s education. It said a study for some private schools found the Department of Education saves €3,500 for every one of the 25,600 students in fee-paying schools.
However, this is far more than the almost €1,000 suggested by the report which shows it would cost an extra €23.5m a year in additional salaries and grants if all 55 schools entered the free education system.