Ambulance personnel are to stage a day-long strike tomorrow in a row over union representation.
The National Ambulance Service Representative Association (NASRA), which is part of the Psychiatric Nurses Association (PNA), said its ambulance personnel members were left with no choice but to strike by the Health Service Executive (HSE).
The one-day national strike is the third phase of industrial action, which started last October in protest at the refusal by the HSE to engage in negotiations with the PNA when representing its ambulance branch.
A PNA member and advanced paramedic, who did not wish to be named, said: "We are striking for our right to join a union of our choice and not the HSE-preferred union, who have not only refused to show solidarity with us, but also now our colleagues and friends in nursing.
"No union should ever divide a workforce and purposefully weaken their legitimate campaign for better terms and conditions. We want nothing more than our choice of union to represent us.
"Well, the HSE and National Ambulance Service management won't let us. They have said numerous times that they will only negotiate with their union, on our behalf.
"Hopefully we won't have to take to the picket lines on Tuesday. Hopefully the HSE will talk to us before then, but it's not looking good."
Contingency plans are in place for emergencies which occur tomorrow.
The union claims to represent 500 of the 1,800 ambulance service employees - including paramedics, advanced paramedics and emergency medical technicians.
The HSE insists that the PNA does not have negotiating rights for the grades in question.
Sinead McGrath, national chairwoman of the PNA ambulance personnel branch, said: "Against the background of the many challenges facing our health services this winter, the public, and indeed our politicians, should be extremely concerned that the HSE is forcing this unnecessary dispute on ambulance personnel.
"Eight years on from its formation, the ambulance personnel branch of PNA is determined not to be dictated to by the HSE in its efforts to force our members to be part of another union.
"I'm again calling on Health Minister Simon Harris, and politicians generally, to demand that the HSE step back from this dispute and move as a matter of urgency to address the issues."