Photographs taken inside Westland High School show the devastating extent of the damage after the fire on Monday.
Teacher Nick Meissel captured the charred scene in what was once the assembly hall, administration block and staffroom on Tuesday, when some staff members were allowed in to retrieve personal affects and important documents.
"The thing that really struck me was that it was so unrecognisable," he said yesterday.
The images show a mess of rubble and debris in what was the hall as well as what remains of the stairway to the staff room and corridor towards the main office.
A report on the full extent of the damage, including the level of smoke and water damage to the adjoining A and B classroom wings, is expected to be completed today.