The HSE has said that all non-emergency operations will be deferred and out-patient appointments rescheduled due to the public sector industrial action scheduled for Tuesday.
Doctors and key laboratory staff will be working on Tuesday.
However, psychiatric nurses and nursing members of the trade unions IMPACT and SIPTU, including many managers, will be on strike.
Nursing unions have agreed to exempt intensive care, coronary care, maternity and some other services from the action.
Care of the elderly and the voluntary intellectual disability sector will also be exempt.
Under the contingency plan agreed with health unions, emergency cover will be provided under the direction of a local strike committee.
A Christmas Day level of service is expected to operate on Tuesday and hospitals have today started to wind down certain services.
Meanwhile, IMPACT has withdrawn strike notice from Cork's Mercy Hospital for next Tuesday.
Cork IMPACT Official Hilary Kelleher said the withdrawal of strike notice was an extraordinary measure for an extraordinary situation.
Hospital management invoked its 'major incident plan' because of flooding in the hospital.
Under the plan all patients are to be moved from the hospital because of flooding and the health and safety risks associated with contaminated water and exposed electricity cables.
Earlier, All unions representing staff in the Courts Service have served notice of industrial action.
There will be major disruption to court sittings and arrangements are being made to adjourn all matters listed for 24 November to future dates.