Thousands of education support workers are set to take part in strike action later this week.
Trade union 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.
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”.
They said a current uplift now being rolled out after months of delay “will still contain within it unfair and inadequate pay levels”.
“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.”
