THE Psychiatric Nurses Association (PNA) has voted overwhelmingly to extend its union to other public service workers, opening the floodgates for a mass exodus of fire and ambulance workers around Ireland.

The move will be of concern to Siptu, which in recent weeks circulated a letter to members of Dublin Fire Brigade – the largest single entity likely to switch affiliation – warning its members not to defect and even to inform on ringleaders.

According to the PNA, it is now expected the union will swell by some 3,500 members, with many already having completed application forms to allow the transfer of funds.

Although the move has been made in the wake of the Croke Park agreement on public sector employment, it is not in direct reaction to it.

"This is not about Croke Park; it's about people who are upset and disappointed with the current structure going back over the years," said PNA general secretary Des Kavanagh, who was first approached on the subject of a potential joint union late last year.

Had fire and ambulance personnel attempted to form a breakaway union on their own they would have run into problems obtaining a licence, but by merging with the PNA this does not arise. The new union is expected to hold a press conference in the next couple of weeks to announce the move.

"The ballot is completed and it was passed by a huge majority so we are now proceeding to take into membership firefighters and paramedics," said Kavanagh.