27 March "D-day for education" warns teaching union
The NASUWT say they will "vigorously oppose" any further cuts to the education budget.
Last updated 11th Mar 2017
The organisation have already staged two days of strike action in Northern Ireland in a dispute over pay, pensions and workload.
Last year all teaching unions here rejected the offer of a pay freeze in 2015/16 and 1% in 2016/17.
The NASUWT is holding its annual conference in Belfast and says any further cuts to the education budget here would be catastrophic for Northern Ireland's education system.
"The incoming administration must engage with the NASUWT to resolve our trade dispute and respond constructively to our request for an improvement to its derisory pay offer." Said the union's National Official here Justin McCamphill.
He added: "We certainly see the 27 March as D-Day for education as well as D-Day for Northern Ireland.
"If it isn't sorted out within four months schools will be facing a 5% across the board cut to their budget."
Earlier this year, the former Education Minister Peter Weir warned schools needed an extra £240m over the next three years in order to maintain current spending levels.
Mr McCampbhill said while the current crisis will hinder education here, it will also have further reaching consequences.
"More schools are reporting deficits." He warned.
"Redundancies, once they start happening, will lead to increased workload, increased sickness absence and increased mental health pressures on teachers.
"This will lead to poor education outcomes for our children and send Northern Ireland back in terms of how it's going to get its economy back up and running again." He also added.