Police have made six arrests as part of an operation investigating historical offending at Dilworth School.

Auckland City Criminal Investigation Branch have been investigating since a complaint was initially made a year ago.

Detective Senior Sergeant Geoff Baber says a team of investigators were brought together to make further enquiries into this complaint and subsequently further offending and victims were identified.

'Six men have been arrested and charged on a number of serious offences that allegedly occurred across a number of decades from the 1970s to the early 2000s.

'At this stage in our investigation we have identified 17 victims.”

A 72-year-old man has been charged in relation to doing an indecent act and three counts of indecent assault.

A 73-year-old man faces numerous charges relating to sexual violation, indecent assault, sexual exploitation and supplying class A, B and C drugs.

A 68-year-old man faces a charge of indecent assault and inducing an indecent act.

A 69-year-old man has been charged with indecent assault.

Police have charged a 72-year-old man faces four charges relating to indecent assault, while a 78-year-old man has been charged with three counts of indecent assault.

'Police are limited in providing any further comment as people are now before the Court.

'We are also mindful of the privacy of the victims involved in these matters.”

The accused are next expected to appear on October 5 and 6 in the Auckland District Court.

'Police are encouraging anyone who may have information that may further assist our enquiries or have matters they wish to discuss about this offending to contact us.

'We would like to reassure anyone thinking of contacting Police that all information received will be treated in confidence.”

Anyone with information can call (09) 302 6624 or email Operation.Beverly@police.govt.nz