Fire investigators are no closer to determining the cause of the fire which destroyed two-thirds of Hawera Intermediate School in Taranaki yesterday.
Four specialist fire safety investigators have spent about five hours at the site today as they try and establish whether the fire was caused by an electrical fault or an arson attack.
Students were asked to remain home today, but teachers and support staff gathered at the neighbouring primary school.
They are aiming to restart classes on Monday.
About 50 firefighters and 13 fire appliances battled the blaze yesterday, which took two hours to bring under control.