Support staff at seven hospitals in Dublin are to hold a two day strike next month as part the escalation in the unions action against Government pay cuts.
Some 4,500 SIPTU members withdraw their labour from 1pm on the afternoon of Wednesday April 7 until 1am on Friday April 9.
Workers who will be downing tools include porters, catering personnel, security, healthcare assistants and supervisors.
The hospitals affected are Beaumont, the Mater, Tallaght, St Vincent's, St James', Blanchardstown, and St Columcilles in Loughlinstown.
SIPTU is warning that low-level action is also anticipated for ambulance services in Dublin, Kildare and Wicklow.
Other hospitals in Dublin will have disputes in the coming weeks whilst action in acute hospitals will be rolled out in the regions.
The move is set to cause massive disruption to the running of the hospitals but the union says the action was inevitable.