FLAMES form the fire at the North Wales Hospital site have been extinguished.
The Fire Service is attending the scene and is in the process of damping down the building.
An aerial platform is being used to pour water onto the joists and beams of the building.
The fire was reported to have broken out in the vacinity of the hall and spread over two floors of the building.
North Wales Fire and Rescue Service were called to the incident
at 08:04am this morning and two crews from Rhyl, a crew from Ruthin, Mold and Denbigh along with the Aerial Ladder Platform from Rhyl are in attendance.