Two more men were charged in February after police claimed they had spoken to more than 100 men who alleged they had been victims of abuse at the boarding school.
The allegations related to offending in the mid-1970s through to early 2000s.
Ross Douglas Browne, Rex Clarence McIntosh, Alister Grant Harlow and two others with name suppression all plead not guilty and will go to trial next year.
Richard Charles Galloway was also among those charged but he died on November 26 last year aged 69 after earlier being diagnosed with cancer.
Former assistant principal Ian Robert Wilson pleaded guilty to the charges and was yesterday sentenced to three years and seven months in prison.
Wilson said in a statement addressed to his victims, and read on his behalf by his lawyer: "I take full complete and absolute responsibility for my actions.
"If you can, I hope you can find some way to heal from my actions."
One of Wilson's victims, Neil Harding, said he was "tasting justice" after delivering an emotional victim impact statement directly addressing Wilson in the Auckland District Court.
Editor's note
It has been a shock for New Zealanders to learn that several former staff at Auckland's Dilworth School have been charged with sex and drug offences against boys over more than three decades. We want you, our readers, to know that the Herald will follow this story wherever it leads. We have a team of journalists prepared to investigate and we want to hear from you. If you have any information please contact us at yourstory@nzme.co.nz
Murray Kirkness, NZ Herald Editor
Where to get help:
• If it's an emergency and you feel that you or someone else is at risk, call 111.
• If you've ever experienced sexual assault or abuse and need to talk to someone call the confidential crisis helpline Safe to Talk on: 0800 044 334 or text 4334. (available 24/7)
• Male Survivors Aotearoa offers a range of confidential support at centres across New Zealand - find your closest one here.
• Mosaic - Tiaki Tangata: 0800 94 22 94 (available 11am - 8pm)
• Alternatively contact your local police station
• If you have been abused, remember it's not your fault.