Dublin's Beaumont Hospital has had 23 new suspected cases of the Winter vomiting virus over the past 24 hours.
As of this morning a total of 83 patients were displaying symptoms consistent with the virus.
The virus is present in 17 out of 19 wards and 40 beds are unavailable because of it.
The hospital is restricting visits and has urged the public to contact their GPs, wherever possible, rather than attending the Accident & Emergency Department.
Elective admissions for medical and surgical procedures at the hospital are postponed until further notice but outpatient services are continuing as normal.