Hundreds of ambulance personnel are set to begin a 24-hour strike from Friday afternoon in a dispute over union recognition.
The industrial action is expected to start at 2pm across the country as members of the Psychiatric Nurses Association (PNA) take to the picket line calling for the right to be represented by the union of their choice.
The union has staged a series of strikes since the beginning of the year over the issue.
The paramedics and emergency medical technicians have chosen the PNA trade union to represent them but the HSE has refused to recognise the union, saying it already recognises a number of unions for ambulance staff.
The PNA represents about 500 of the 1,800 National Ambulance Service staff.
The majority of the staff are members of the Siptu trade union.
Earlier this week Siptu confirmed that members working in the HSE’s National Ambulance Service are set to ballot for strike action in a dispute over a new payroll system.
Siptu said on Monday that the potential industrial action would involve ambulance personnel in Dublin, Wicklow and Kildare.