Hospital management apologises for the inconvenience to patients.
People are being advised to only attend Mullingar Emergency Department if absolutely necessary.
Management says the facility is still very busy and is apologising for the inconvenience to patients and their families.
They say anyone seriously injured or ill will be assessed and treated as a priority and are asking people not to bring children.
The hospital is asking people to consider their care options, telephone their GP/or pharmacist in the first instance to seek the best advice, rather than presenting at the hospital.