Flood damage at Letterkenny General Hospital will cause further delays for patients waiting for surgery.
Management at the hospital said it is not clear when it will be back to normal.
The clean up operation is continuing at the hospital after the flooding two weeks ago.
A temporary emergency department will be constructed in modular buildings combined with mobile diagnostic units already in place.
Key corridors have been decontaminated in the wake of floodwaters which knocked out 70% of the hospitals services.