Siptu have confirmed that its union members working in the National Ambulance Service (NAS) in Dublin, Wicklow and Kildare will be balloted for industrial action.
They said the action could include a strike over problems with a new payroll system.
Siptu Industrial Organiser, John McCamley said: “Despite repeated calls to fix the IT problems and numerous engagements, NAS management has failed to resolve this matter to our members’ satisfaction.
"We have members who depend on every cent they earn to pay mortgages and childcare costs, left in the intolerable position of being short-changed on their overtime, bank holiday and subsistence payments for over five weeks now.
"We regret taking this action but our members have been left with no option.
"They perform an essential public service and are now in limbo with no sign of payment on the horizon. It is not acceptable."
"The dispute also involves the unilateral withdrawal of subsistence payments for ambulance professionals in some circumstances.”