The Government has been accused of creating a rift in schools after awarding a #163;250 pay boost to unqualified teachers while failing to enforce any rise for support staff.
Chancellor George Osborne had promised extra money to all public sector workers earning less than #163;21,000 in last year's emergency budget, despite a two-year pay freeze for those on higher salaries.
The Department for Education this week announced that about 7,350 unqualified teachers will receive extra payments of #163;250 both this year and next year.
But the move follows a decision by local councils not to award a rise to thousands of low-earning support staff, prompting criticism from unions and demands for meetings with ministers to push their case.
Jon Richards, senior national officer for Unison, which represents about half of the country's 400,000 support staff, said: "If the point of the #163;250 payment was to soften the blow for the lowest earners, there is a tragic irony in the Government's behaviour.
"We do not begrudge teachers or any other group who will receive the increase, but to deny it to those who work alongside them and who may remain in low pay throughout their career is shocking. This is another blow to the concept of the school workforce as a team."
Brian Strutton, national secretary the GMB union, added: "People are working side by side doing very similar jobs in the classroom but why is it that one worker can have #163;250 and the other can't? It is incomprehensible. You try explaining that to a school support staff worker."
The Government has denied it is responsible for the pay decisions of local authorities, with the Treasury insisting that council pay "remains a matter for negotiation and agreement between employers and unions".
"But we have made clear that we expect local government to show restraint on pay in line with the rest of the public sector as well as seeking to provide the lower paid with some protection from the impact of pay restraint," a Treasury spokeswoman added.
In a letter to unions, the Local Government Employers said offering the #163;250 payment to support staff and other council workers would increase local authorities' pay bills by #163;265 million and add to a #163;6.5 billion funding gap. They said protecting services and jobs should "take priority" over any increase in pay.
Meanwhile, teaching unions are also unhappy with the #163;250 deal that has been confirmed for unqualified teachers. Unions had argued for it to be added onto salary each year, meaning staff would get #163;250 extra in the first and #163;500 in the second.
However, ministers have decided the money will come in the form of two one-off payments. This, according to the School Teachers' Review Body, will save the Government about #163;2 million.
Martin Freedman, head of pay at teaching union the ATL, said: "Low-paid workers aren't being protected from the pay freeze; they will be taxed on this so they will get very little."
NUT general secretary Christine Blower agreed that the one-off payments did not amount to a pay increase for the low paid, but stressed the key issue was the "scandal" of the pay freeze being imposed on other teachers.