Children's services are being temporarily relocated from Tallaght Hospital to Crumlin and Temple Street, as well as the urgent care centre in Blanchardstown.
Most children's health services, including inpatients, day cases and the paediatric emergency department in Tallaght will close from today.
The outpatients department will stay open, as well as virtual clinics and specialist outpatient services to support patients who attend with chronic needs.
This will make space in the hospital for coronavirus patients and an "unprecedented demand on acute services, especially adult healthcare".
The relocations are a part of contingency plans in light of the ongoing coronavirus crisis and will see Tallaght University Hospital used for additional bed capacity, staff and emergency facilities in dealing with sick adults.
Other CHI hospitals in Crumlin and Temple Street will also remain fully open, as well as the urgent care centre in Blanchardstown.
Paediatric emergency medicine consultant and paediatric executive lead at CHI at Tallaght Dr Ciara Martin said: "It is so important that all of us within the health service take whatever steps are possible to ensure that we direct resources where they are most in need."
She said that the move from Tallaght Hospital is temporary and that services will reopen when "we get through this pandemic".
"The measures announced today for CHI at Tallaght are temporary, but necessary.
"I want to thank our staff for their dedication, responsiveness and flexibility during these unprecedented times and also want to reassure parents and families we continue to offer all necessary paediatric services at CHI at Crumlin, Temple Street and Tallaght and we will reopen paediatric services at Tallaght when we get through this pandemic," she said.
Children over 16 years of age are advised to attend an adult emergency department service, unless directed otherwise.
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