The Department of Education spent more than €104 million on the salaries of teachers in private schools last year.
According to Freedom of Information figures released to Newstalk, the bill for two schools in Dublin was over €4 million.
The department pays the salaries of teachers in over 50 fee-paying school across the State.
In the 2021-2022 school year, this cost the State €104.3 million.
It is only €13,000 more than the previous year, but €7 million more than in 2019-2020.
The highest amount last year was paid to teachers in St Andrew's College in Dublin, at almost €4.2 million.
Another school in south Dublin - Blackrock College - was next at just over €4 million.
Both of these schools had more than 1,000 students during the year.
Gary Gannon, Social Democrats Education Spokesman, said it is not appropriate for the State to fund the salaries of teachers in private schools.
"What I can't accept is the State continuing to allow wealthier cohorts of society to lock in their privilege, through investing in private education, that is bucked up by the State's investment of over €100 million coming from the taxpayer," he said.
Deputy Gannon said this was being used "to fund a rather small cohort of people to ensure that they get more advantages going into the Leaving Cert, and inevitably into the best places in third-level education."
In total, the salaries of teachers in seven private schools across the State came to over €3 million last year.