The Children's Hospital in Tallaght in Dublin has reopened, however it will not offer full acute services.
According to Children's Health Ireland, the hospital will redirect critically ill and critically injured children to the Emergency Departments at Crumlin and Temple Street hospitals.
It will also no longer deal with paediatric surgical inpatients.
Dr Ciara Martin, consultant and paediatric executive lead at Children's Health Ireland said the hospital has changed the way it manages surgical inpatients, and these changes will affect around six children a day who would normally be treated in Tallaght.
Speaking on RTÉ's News at One, she said children with conditions including acute appendicitis or those who require surgical intervention have been treated in recent months by consultants who work across the three children's hospitals in Dublin.
Dr Martin said those children who require emergency surgical intervention usually arrive by ambulance.
Moving these patients to two hospitals - Crumlin and Temple Street - will offer them the best care as hospitals continue to operate in a Covid-19 environment, she said.
At Tallaght, the 40 in-patient beds and eight short stay beds reopened this morning for medical conditions other than surgical patients.
If a child has severe abdominal pain or trouble breathing, they should go to Crumlin or Temple Street, Dr Martin.
In March, acute services for children were temporarily relocated from Tallaght to Crumlin and Temple Street due to Covid-19.
This was to support Tallaght University Hospital's adult services with additional staff, emergency facilities and bed capacity.
The children's hospital at Tallaght was due to reopen last Monday.
As part of the new National Children's Hospital structure, Tallaght is moving towards opening a new outpatient and urgent care centre in 2021.
Tallaght will provide paediatric medical inpatient, day case surgery, medicine, x-ray and outpatient services.