Inspector Mark Fergus, Area Commander of the Rodney Police said the arson was extremely disappointing.
"Not only the College but also the community. We can't speculate on the motivations of whoever lit this on fire but we're very keen to hear from anyone who may have observed suspicious behaviour in the area on Monday night, or from anyone else who can provide us with information."
The site was blessed on Tuesday morning by a local Kaumatua.
Anyone with information is asked to contact Senior Constable Ian Price, Whangaparaoa Police on 09 947 5137.
Information can also be given anonymously to the organisation Crimestoppers on 0800 555 111.