Thousands of education support workers are set to take part in strike action later this week.
Trade unions Nipsa and Unison said there will be picket lines at hundreds of schools across Northern Ireland during the action on Thursday.
The move comes amid a dispute over pay.
Nipsa said their members involved in the action also work in support services and Education Authority headquarters.
They described the action as being around four points: pay and grading review, job evaluation, pay differentials, and education cuts.
They said their members have been engaged in action short of strike action since November 6, after an “overwhelming ballot endorsed the plan”.
The strike action on Thursday has been described as the first escalation of the action and will consist of two hours of strike action.
Nipsa official and lead joint trade union side secretary Education Authority representative Alan Law said there is a real anger among education workers.
“They feel that the true value of their contribution to the delivery of education has been ignored for too long,” he said.
“They resent being ignored. They are right to feel angry.
“The delays in progressing the matters in this dispute which seek to reform their pay structure, make it fit for purpose and futureproof it just adds insult to injury.
“The current action has demonstrated just how much EA school-based and HQ staff do that is outside their job description. This goodwill has ended and won’t be returning.”
Unison said the workers are “sending a strong message to the Education Authority, the Department of Education” as well as members of the collapsed Northern Ireland Assembly, that “reform of their pay structure is long overdue and must be addressed without further delay”.
“Fence-sitting and hand-wringing by the department will no longer placate education workers,” they said.
“They must mandate the employer to open negotiations towards a settlement of this dispute.”
DUP MP Carla Lockhart has urged the Northern Ireland Secretary Chris Heaton-Harris to intervene – in the absence of a functioning Stormont Assembly and Executive – saying that many schools will be unable to open during the strike.
She said both staff and parents are frustrated.
“We need solutions to this dispute, and the person who can resolve it is the Secretary of State,” she said.
“His ongoing denial that he has the power to act is verging on the ridiculous now when he has stepped into other aspects of education provision here.
“He should deliver the deal for staff that brings this dispute to an end, and do the right thing by staff, parents and pupils.”
Department of Education permanent secretary Dr Mark Browne said the strike action “will undoubtedly cause significant disruption to services right across the education sector and have a major impact on parents and pupils, including our most vulnerable children and young people”.
He described the move as “disappointing”, saying a pay award, which covers non-teaching staff, was agreed on November 1 for 2023-24.
It has been provided to the Education Authority to allow the award to be implemented as soon as possible.
“I would urge everyone concerned to reconsider, in light of the serious ramifications of this strike and the severe disruption that will be caused,” Dr Browne added.
Subscribe or register today to discover more from DonegalLive.ie
Buy the e-paper of the Donegal Democrat, Donegal People's Press, Donegal Post and Inish Times here for instant access to Donegal's premier news titles.
Keep up with the latest news from Donegal with our daily newsletter featuring the most important stories of the day delivered to your inbox every evening at 5pm.