SCHOOLS that together overspent their budgets by more than £62 million this year can make no more savings, it has been warned.
More than 450 schools in Northern Ireland are in deficit, according to the Education Authority (EA).
A Westminster inquiry found that since Stormont collapsed in early 2017, a growing funding crisis had resulted in "unmanageable pressures" on schools.
It said increasing numbers of children with special needs were adding to pressure on school finances.
Unions have said members have had to dip into their own funds to buy classroom materials and even food, clothing and toiletries for children.
Some claimed they got themselves into debt because of purchasing items for lessons.
It has been warned that schools are being forced to squeeze more children into classrooms, and reduce the number of subjects they can teach.
Now, in a letter to school principals, EA chief executive Sara Long has spoken of the growing frustration.
Ms Long said the EA acknowledged the challenges to meeting the diverse and increasingly complex special educational needs of children.
"We acknowledge your growing frustration with the lack of adequate funding to enable you to fully deliver high-quality learning experiences for all children and young people," she wrote.
"While the submission of your three-year financial plan may cause anxiety, we want to stress that this will provide us with the evidence necessary to capture the shortfall and to call for additional funding now and in the future.
"You and your governors are thanked for the commitment you have shown in seeking solutions to financial shortfalls and in making savings. We realise that for some schools there is no more that can be done to effect any further savings."
