Dilworth School is being praised for its cooperation into a sexual violence investigation

Headmaster of the Auckland private boys' boarding school, Dan Reddiex , says the recent charges are appalling and deeply saddening.

A seventh person has been charged following an investigation into the school, where it's alleged at least 17 boys were sexually abused between the 1970s and early 2000s.

National sexual violence advocate Louise Nicholas thanks the school - for not sweeping it under the carpet.

She says they're supporting past students, and reiterating that this won't happen again.