A decision on planning permission for the new National Children's Hospital has been delayed, RTÉ News has learned.

An Bord Pleanála has decided to extend the time period by which it will give its decision on planning permission for the proposed new National Children's Hospital.

The decision had been expected by next Monday but will now be made by 12 May.

It is in the process of notifying the various interested parties of the extension, which it says is due to the complexity and the number of issues involved.

Oral hearings were held last year into the project, with the hospital due to be built at the St James's Hospital campus.

The planning application was submitted for the project last August.

The €650 million hospital is due to by opened by around 2020.