Ambulance staff have announced that they are to go on strike for three extra days in the coming weeks.
Members of the National Ambulance Service Representative Association (NASRA), the personnel branch of the Psychiatric Nurses Association (PNA), are to hold the work stoppages on Friday, February 15, Thursday, February 28 and Friday, March 1.
Around 500 PNA members will strike over a dispute on trade union representation rights from 7am to 5pm each day.
The General Secretary of the PNA, Peter Hughes, said the strike days are a considerable escalation of the industrial action taken to date.
He said it shows the resolve of ambulance personnel to be represented by the union of their choice, and not by a trade union that the HSE wants them to join.
"Against the background of the myriad of serious problems in our health services, it is beyond belief that the HSE, in continuing to confront over 500 PNA ambulance personnel members on this issue of fundamental worker rights," he said.
Sinead McGrath, National Chair of NASRA, called on the Minister for Health Simon Harris to avoid further escalation in the dispute and to instruct the HSE to engage with the industrial relations machinery to end it.
The announcement follows a strike held on January 22 by ambulance staff around the country.