Regional Hospital Mullingar is advising the public to speak to their GP or pharmacist rather than presenting at the Emergency Department.
The hospital said the ED is "extremely busy".
Management have also asked that visitors only attend the hospital if "absolutely necessary" and not to bring children if possible.
In a statement it said: "Hospital management apologises for the inconvenience to patients and their families and thanks the public for their cooperation at this time.
"Regional Hospital Mullingar would like to assure people that anyone seriously injured or ill will be assessed and treated as a priority."
