The Mater Hospital in Dublin says it is limiting all activity to "essential services only" over the COVID-19 outbreak.
From today, most outpatient appointments and elective surgeries are being deferred until further notice.
Hospital management said it regrets the impact it will have on patients but the move is necessary "to deal with the impact" of the coronavirus.
All patients who are having appointments deferred are being contacted by the hospital.
In a statement, Mater management said: "Our staff across every part of the hospital are carrying out trojan work around the clock to deal with the virus, care for those infected and to protect and care for other patients in the hospital.
"The Mater Hospital is employing all infection control measures and every effort is being made to manage and control the spread of the virus."
Visitor restrictions are already in place at the hospital and will remain in place.
The only visitors being allowed are those visiting patients in critical care, vulnerable young adults, and those whose loved ones are receiving end of life care.
No children are being allowed to visit "under any circumstances".
Similar restrictions are in place for visitors at hospitals across the country amid the rising number of coronavirus cases here.
In the Republic, 43 cases of COVID-19 have now been confirmed, after nine more were confirmed yesterday evening.
