The trade union SIPTU has said plans to close a ward in University Hospital Limerick is a breach of the terms of the Public Service Stability Agreement (PSSA).
The union has claimed management is proposing to close the ward without consultation with unions.
SIPTU organiser Pat Condon said: "Union representatives met with senior management on January 9th.
"At this meeting, management said it was proposing to close Ward 1A in order to facilitate the opening of a fracture unit in its place."
"SIPTU representatives stated that Ward 1A was part of a 2016 agreement for the opening of a new emergency department for the hospital.
"We pointed out that it was senseless at this point to close a 16-bed unit when the hospital was effectively operating beyond capacity with trolleys on wards every night.
"We highlighted that removing these 16 beds would adversely affect patients and expose our members to dangerous risks."
SIPTU has said agreement was reached that these beds would remain open, and that if there was to be any change management would re-engage with union representatives.
But Mr Condon said: "Our members are upset to learn that management proposes to go ahead with the closure of this ward at the end of March.
"This is despite there being no further discussions on this issue between management and union representatives."
He claimed management has also "refused to meet with unions" to discuss the wider issue of staffing levels in the hospital.
"Unless there is an immediate engagement by management with our union, the next step will be to cite this breach of the PSSA to the National Implementation Body, which is responsible for overseeing adherence to the agreement", he added.
It comes as University Hospital Limerick has 54 people waiting for a bed, according to the INMO's latest Trolley Watch.
This breaks down as 35 people on a trolley and a further 19 on a ward.