Speed camera van workers are to strike over the October Bank Holiday.
GoSafe operators who're members of SIPTU will take part in a 72 hour stoppage from 9am on Saturday the 26th.
The escalation comes as part of the unions ongoing dispute with the company over staff working conditions and union recognition.
It follows similar action last month which saw operators down tools for 24 hours.
SIPTU Organiser, Brendan Carr, said the action is a "last resort" and accused the company of “intransigence” with management refusing to address concerns health and safety and conditions of employment.
He said management had ignored a Labour court recommendation urging it to recognise SIPTU as the representative of its employees who are union members.
He also took aim at the Government for hiring a "company which imposes inhumane working conditions on its employees."
The union has said staff can be stuck in their vans for up to 11 hours per shift.
