INMO representatives say plans by the HSE to open decommissioned beds in Nenagh hospital without additional staff will compromise patient safety.
Following a ballot of all its members in the UL Group of hospitals, due to the severe overcrowding problem and opening up beds without taking on more personnel, nurses have voted by 93 percent to take industrial action.
The group includes Nenagh General Hospital, University Hospital Limerick Ennis, and Croom Orthopaedic hospital.
The work to rule will begin on Tuesday, February 3rd.