Work began yesterday on the partial demolition of the former Port Kembla school building which was gutted by fire on January 3.
Everything above the ground floor windows is expected to be demolished to make the site safe so police can enter to investigate the cause of the blaze.
A key concern during the works will be asbestos, some of which fell onto the ground immediately outside the heritage listed building after it was gutted by fire.
Lake Illawarra police are investigating the fire and are expected to enter the building when deemed safe.
The fire is thought to have broken out in one of the upstairs fireplaces, in a room once used as a classroom.
Authorities suspect arson as the cause.