The nurses' strike is to go ahead after the Labour Court decided not to make a formal intervention in the dispute over pay and staff shortages.
More than 25,000 patients will have medical appointments disrupted due to tomorrow's national nurses' strike, according to the Health Service Executive.
Exploratory talks at the Labour Court yesterday were adjourned early this morning, and the court this afternoon decided not to make a formal intervention in the dispute.
The HSE has put contingency plans in place around the country as the 24-hour stoppage by members of the Irish Nurses and Midwives Organisation (INMO) is due to start at 8am tomorrow.
More than 35,000 nurses are expected to strike.
In a statement, the INMO's Director of Industrial Relations said the union is "deeply disappointed" that the Government has "no serious proposal to resolve this dispute."
"No nurse or midwife wants to go on strike, but we have been forced into this position by a Government that just isn't listening," Tony Fitzpatrick said.
At a briefing this morning, the HSE revealed that in addition to 13,000 hospital outpatient appointments and 2,000 surgeries being cancelled, a further 10,400 appointments in community care services will be postponed.
Of those community care cancellations, 1,500 will affect day-care for the elderly, while a further 1,500 will hit day centres for adults with disabilities.
Another 7,000 primary care contacts will also be cancelled.
However, planned cancer surgery will proceed, and an exemption has been secured for disability services in residential units.
So-called Section 39 bodies in health and social services will also operate as normal.
If the INMO were to strike on all six scheduled days, it would add 150,000 patients to already lengthy waiting lists.
In addition, tomorrow's disruption does not include planned industrial action by the 6,000 members of the Psychiatric Nurses Association, who will commence an overtime ban on Thursday - gradually escalating to three full strike days on 12,13 and 14 of February - when the INMO will also be on strike.
The nursing unions argue that only an across-the-board pay rise for nurses will make the profession sufficiently attractive to attract and retain personnel.
However, the Government insists that the €300m claim is unaffordable, would breach the current Public Service Stability Agreement, and would trigger widespread costly knock-on claims.
Doctors concerned over prioritising sickest patients in ED - IAEM
The President of the Irish Association of Emergency Medicine has said doctors are concerned they will not be as good as they should be at prioritising the sickest patients first in emergency departments if the strike goes ahead.
Emergency departments will be open during the strike action, but there will be reduced staff levels.
Dr Emily O'Connor said nurses are absolutely essential for both the running and the prioritisation of patients in EDs.
Speaking on RTÉ's Today with Sean O'Rourke, she said: "About 3,500 to 4,000 patients attend at Irish emergency departments every 24 hours.
"We do pretty well at seeing the sickest and the most injured early, but as we all know other patients who are less sick and less critically injured do have to wait for care on occasion.
"The differentiation of those two groups is entirely dependent on what we call Manchester triage, which is a prioritisation system that's entirely delivered by nurses in the Irish healthcare system. Doctors aren't trained to do this, its not something we can step up into.
"So there's a lot of concerns that we won't have enough nurses and that in particular we won't have a nurse to triage patients as they come into the emergency department. That means we have concerns that we won't be as good at plucking out the sickest to be seen first."
Meanwhile, INMO figures show there are 587 patients on trolleys or on wards waiting for admission to a hospital bed.
The worst affected hospitals are University Hospital Limerick with 59 patients on trolleys; Cork University Hospital with 56 and 53 at University Hospital Galway.
The figures show that 427 patients are waiting in emergency departments around the country, and 160 are in wards or elsewhere in hospital.