The recent National Association of Head Teachers conference has sparked debate between headteachers, with some saying that government ministers are not listening to them.
Headteachers at the Telford conference backed a motion giving their leaders licence to explore all available options - including a shorter school week to protect education standards. The government insists school funding has never been higher and says funding will rise to £41bn in the next year.
Head teacher Graham Frost said at the conference that the line from the government was like "a recorded message" that came back every time the issue was raised, and this was driving heads "crazy".
"We are not advocating a four-and-a-half-day week, we are just so despairing".
He added that dropping teacher hours could be necessary if a school did not have the staff to run classes safely. Alternatively, a head may make this decision to prevent schools from axing support staff for children with particular needs.
Another head teacher, Clem Coady, claimed: "The four-and-a-half-day week must be seen as the very last resort because we don't want to cut the offer we are giving to children, to parents, to families, to our staff. But there has to be some way of forcing and opposing these government imposed cuts - they have got to overturn it."
The motion also gave the NAHT executive the right to encourage its members to take other steps, such as running deficit budgets in schools or refusing to file budgets to local authorities. The NAHT will discuss further steps in its campaign to oppose school funding cuts at an executive conference in June.