The HSE says that talks are ongoing with the INMO to explore if arrangements can be made to allow for major surgeries, including cancer procedures, during tomorrow's nurses' strike.
It says if the exemptions are agreed, then patients will be contacted directly by their hospital.
Nurses and midwives will take to the picket lines from 8am tomorrow.
All outpatient, inpatient and day surgery appointments are cancelled for tomorrow, and Minor Injury Units will be closed.
Community nursing services and public day centres will not be operating and planned admissions are all cancelled.
The HSE says that hospitals will re-schedule appointments in due course.