A Church of Ireland archbishop has called on fee-charging Protestant schools to open their books to state officials.
Dr Michael Jackson encouraged schools under Church of Ireland management to take part in a Department of Education study on spending.
Dr Jackson, Archbishop of Dublin, welcomed the audit by the Republic's Education Minister Ruairi Quinn.
"This initiative provides an opportunity for all such schools to show the ways in which fee income is being used to supplement the resources of individual schools," he said.
The churchman said it was important to recognise and maintain the network of schools so students of minority denominations could attend a school which lives out the Christian ethos.
"This audit will enable schools to demonstrate to the minister if they are in difficulty and why this is the case," he added.
Mr Quinn has ordered his officials to conduct an audit into the estimated 120 million euro spend by schools, including the nature of the Exchequer investment, including funding for teacher posts.
It will also involve looking at the level of the tuition fee income based on fee rates and pupil numbers and take.
Dr Jackson revealed that during a meeting with Mr Quinn at Leinster House before Christmas, the minister was anxious that Protestant secondary schools would engage with his department.
"For my own part, I encourage all fee-charging schools under Church of Ireland management to participate and co-operate in this initiative," he added.