12 fee-paying schools are considering dropping fees because parents can no longer afford to enrol their children.
The Irish Independent reports this morning that the schools have begun talks with the Department of Education about changing their status.
Those 12 schools represent more than 20% of the 55 fee-paying schools in the state.
Fine Gael TD Mary Mitchell O'Connor said the state would not be able to fund all 55 fee paying schools if they became public.
"First of all, they may have to buy the school out. Second of all, they have to pay for all the children - all the capitation grants, everything else.
"So at this moment in time, if 55 schools arrived back in the morning into the public system, we can't – we have to be realistic," she said.
In addition to falling enrolment numbers, fee-paying schools are also facing cuts from the state when it comes to teacher numbers.
Labour's Aodhan Ó Riordáin also said he was concerned about adding additional schools to the public system.
"It would mean that the state is now liable for the capitation grants of each student … essentially the state would have to do what it odes for every other non-fee-paying school in the country," he said.