Staff were devastated at the damage, with one teacher losing all teaching resources.
"We will have to start from scratch but, teachers being teachers, they have lots of resources. Yesterday they arrived with plenty of stuff to give to her.
"Furnware have arrived with little chairs, because we had the children sitting with their legs dangling, and Mahora School have arrived with little tables."
The children were upset at losing their classrooms "but have probably coped the best". News of the fire had hit parents and past students hard.
"We have a very good supportive community that have really rallied around. I have spent the last two hours responding to emails of support from the education and local community, which we are very grateful for."
Police are looking for the owners of a softball bat found at the scene with the words "Regent" and "Rocket" stencilled in blue, believed used in an attempt to smash a glass classroom door before the fire was started at about 5.30pm.
"We are very keen to identify the owner of the softball bat, or find out any information about its origins," detective Ross Alexander said.
"It is quite distinctive and someone will know who it belongs to. It is important that we speak to anyone who has any information about this fire, which has done major damage to the school," he said.
Police are keen to speak to anyone who may have noticed people acting suspiciously around the school on Sunday afternoon and early evening.
"This fire has had a serious impact on one of our local schools and has deeply affected both staff and pupils, who are very upset about losing their classrooms.
"Hopefully someone can provide information that will help us find those responsible so they can be held accountable for their actions," Mr Alexander said.
Anyone with information about the fire should contact Mr Alexander at Hawke's Bay Police on (06) 831 0700 or information can be left anonymously on Crimestoppers 0800 555 111.