Primary school principals from across Northern Ireland have held a crisis meeting over school budgets.
They insist they have no choice but to put their schools in deficit, despite a fresh warning from the Department of Education not to.
The funding dispute began after a letter was sent to schools in March from the department's finance director Gary Fair, who has taken charge in the absence of any Stormont minister.
With no budget for the next school year yet agreed, he advised principals they may have to implement funding cuts of up to 6%.
In response, head teachers at 43 Belfast primary schools wrote to parents expressing their "grave concern" over the "impossible" cuts, adding that in order to protect basic services they would be forced to make decisions which would put schools in deficit.
Mr Fair issued a second letter to schools on Tuesday warning them against going into the red.
The letter stated: "While I appreciate that the majority of schools will continue to exercise budgetary discretion and firm financial management, some principals have indicated that, even in doing so, they may be forced into deficit positions.
"What is of more concern is that some have also stated that they will be planning for deficit budget positions over the next three years.
"No school may plan for a deficit without the consent of the Education Authority."
Yesterday, the number of concerned principals grew as 50 heads from Belfast, Mid Ulster, Lisburn and Newry met.
Speaking after the gathering, Stranmillis PS head teacher Jackie Wallace denied he or his colleagues would be spending foolishly.
"That is not the strategy - we've no choice," he said. "We either cut the core services, meaning no luxuries, or our budgets are going to go into the red. We're not prepared to cut into the bone and fail our children."
Mr Wallace said he believed the concerned group of principals would soon have the backing of a large number of schools.
UUP MLA Rosemary Barton, a former teacher, said she feared "this bubble will burst" after years of mounting financial pressures on schools.
She said nothing would change without political agreement at Stormont.
"Whoever takes this ministerial position must take the financial crisis in our schools extremely seriously and prioritise front line funding in the classroom over everything else," she added.