The HSE has shut down all of its IT systems at a local and national level in response to a "significant and serious" cyber attack.
It is understood the HSE was targeted in what is known as a 'zero day' attack, meaning the criminals exploited a vulnerability which was not known to the HSE.
The HSE became aware of the attack in the early hours of the morning, chief executive Paul Reid confirmed, and shut down its system nationwide in an attempt to stop the attackers doing further damage.
The extent of the damage to the HSE system is not yet known, but Health Minister Stephen Donnelly said it is having “a severe impact” on health and social care services.
Covid-19 vaccination appointments are going ahead as normal.
The HSE's Covid-19 test referral system is no longer operational. Patients have been advised to attend any walk-in Covid-19 test site if they need a test, with priority given to symptomatic people and their close contacts.
However, if you already had an appointment for a Covid-19 test, this will go ahead and you should attend as planned.
People who had a recent Covid-19 test appointment and are awaiting their results will still have their tests processed in our laboratories but have been advised there may be some delay in receiving their test results.
The HSE has warned it is critical that anyone who is awaiting a Covid-19 test result, self isolates until they receive their test result. This is an important change from the usual restricting movements advice.
Radiotherapy appointments are cancelled at CUH today. Most X-ray appointments are also cancelled.
Patients have been advised to attend their appointments if it is for chemotherapy, surgery or an out-patient appointment.
Labs are severely affected and only emergency bloods will be processed at this time.
Emergency services are continuing across the group’s hospitals including the Emergency Department at UHL, injury units at Ennis, Nenagh and St John’s hospitals and the Early Pregnancy Assessment Unit/Maternity Emergency Unit at University Maternity Hospital Limerick.
UHL has advised outpatients with appointments to still attend but warned they can expect delays.
At University Hospital Galway, outpatient, chemotherapy and maternity appointments are continuing. All outpatient x-ray, CT and MRI, and radiotherapy appointments are cancelled.
Outpatient radiology appointments including x-ray are also not taking place today in Merlin Park University Hospital Portiuncula, University Hospital Letterkenny, University Hospital Sligo, University Hospital Mayo and University Hospital Roscommon.
Patients have also been advised to expect delays in all clinics and in injury units today as existing IT systems are not in use and the manual workarounds are time consuming.
All routine appointments have been cancelled today across St Luke's Radiation Oncology Network sites which include St Luke's Hospital, St Luke's Centre at Beaumont Hospital and St Luke's Centre at St. James's Hospital.
All X-ray appointments at Wexford Hospital from May 17 are cancelled. All endoscopy procedures scheduled for Monday 17 in Ely Hospital have also been cancelled. Maternity services will continue as normal.
All OPD services at St. Luke's General Hospital Carlow/Kilkenny are cancelled on Monday 17, apart from antenatal clinics. Routine X-ray, physio and cardiac diagnostic appointments are also cancelled. Maternity services and emergency services are running as usual.
All ophthalmology outpatient services at the Royal Victoria Eye & Ear Hospital are cancelled until further notice. Emergency and urgent care remain open.
Radiology at St Columcille's Hospital Loughlinstown has been cancelled today.
All services at Our Lady’s Hospital, Navan are running as normal.
The group has asked patients to attend appointments as scheduled unless they hear otherwise from their hospital. Patients who have scheduled appointments for next week have been advised to pay attention to updates on services as hospitals may not be able to access information in order to call and cancel appointments. IEHG will provide updates via its Twitter account.
All appointments cancelled except for emergencies and women 36 weeks pregnant or later.
Patients with appointments and anyone who needs to attend the hospital today has been advised to do so but the NMH has advised there will be “significant disruption” to all services today.
The HSE has advised patients to attend appointments as planned if they are not in the above list.
Most hospital appointments are still going ahead as planned, they said, but delays should be expected as hospitals move to manual, offline processes.
The child and family agency has advised its internal systems, email and portal through which child protection referrals are made are not operating. Any person wishing to make a referral about a child has been advised to do so by contacting the local Tusla office in their area.
The national ambulance service continues to take calls and operate as normal.