The construction of the new National Children's Hospital is falling behind schedule.
The HSE has warned that the project is facing delays which could affect critical timelines.
Work on some parts of the National Children's Hospital at the St James site in Dublin are behind schedule.
HSE Chief Executive Paul Reid has written to board members to warn them that the delays could lead to important deadlines being missed.
According to the Irish Times, a revised timeline for the project is being developed - which will set out mitigation measures.
The Hospital is currently due to open in April 2023.
The estimated cost of the project has risen by €450m euro to €1.7bn since it was first announced by the government.