Fórsa union members at Oberstown Children Detention Campus will take part in an eight-hour work stoppage later today.
The action, which will take place from 9am to 5pm, is due to a continuing dispute over resourcing and safe staffing at the campus.
It is the second in a series of planned weekly work stoppages, with further stoppages to take place on 18 August and 25 August.
The ongoing industrial action follows a ballot of Fórsa members, concluded in May, which backed industrial action, up to and including a full withdrawal of labour.
Oberstown staff have been engaged in a work-to-rule action since 25 June.
Union negotiators and management at the centre were unable to reach an agreement on key issues.
The union said it was frustrated that no representative of the Department of Children was present.
Fórsa national secretary Hazel Nolan said safe staffing in Oberstown has been a “long-standing concern” for staff, and that members want a “lasting solution”.
“We agree with management that staff safety and the safety of the young people in Oberstown are inseparable.
“Unfortunately, talks have broken down because Oberstown is refusing to include key elements of our claim in the business case going to the department.
“This includes measures to address the recruitment difficulties facing the service.
“Management says these issues should be dealt with separately through ‘local bargaining’, while also acknowledging that there is not enough money allocated to the local bargaining budget to resolve them,” she said.
“Fórsa cannot enter a process when we know from the outset that it cannot resolve the claim.
“Our members need a genuine, long-term solution to safe staffing, and that is what we will continue to pursue,” Ms Nolan added.