The National Association of Principals and Deputy Principals says many schools will be short of teachers when they return next week.
There are currently over 400 classroom vacancies at second level.
However the Department of Education says it is actively doing as much as it can to recruit teachers.
Paul Crone is the director of the NAPD:
"We're hearing it from our regions. We're hearing it from our National Executive. And the phrase being used by principals is 'We're at crisis point'. We have schools opening next week and I haven't come across a single school that has said to me they have a full cohort of teachers ready for the opening of next week".
