Of the 53, 28 committed suicide, 12 died in road crashes, six drowned, four died in falls, two from alcohol poisoning and one died after inhaling butane.
Twelve had left or been excluded from school before their 16th birthday.
Starship Childrens Hospital acting director of child health Dr Mike Shepherd said the findings, presented at the Children in Crisis Conference in Hamilton yesterday, were tragic but not surprising. "They're a reinforcement of some existing knowledge so to that degree it really does emphasise the nature of this problem."
He said the ADHB was working with schools and primary health care organisations on a strategy that tries to identify at-risk children before their problems start, including having nurses at lower decile schools to screen for issues and helping children and their families.
"Our view is that we are trying to do stuff at the top of the cliff ... hopefully we are going to be able to identify these young people much earlier and keep them involved in school."
Child and Youth Mortality Review Committee chairman Dr Nick Baker said groups were working with police, CYF, the Ministry of Education and Transport, hospitals and schools to identify the levels of support needed.
He said there was a pattern across the country among youth who were experiencing "accumulating adversity" like being stood down, exposed to domestic violence or being in CYF care.
"Of course one of the things is that if you get stood down you're often in a home environment that hasn't nurtured you sufficiently to keep you out of trouble and you have less supportive influences so it's really no surprise that bad things happen."
Secondary Schools Principals Association president Tom Parsons said the number of exclusions, expulsions and stand-downs was declining and schools worked hard to retain their pupils but there were serious concerns for those who slip through the cracks.
"Where they go to from there is very problematic because there is no catcher out there and no safety net out there for those students so the next time they come into authority's view is in the courts or A and E and so on."
Where to get help
• Youth services: (06) 3555 906
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (4pm to 6pm weekdays)
• Whatsup: 0800 942 8787 (noon to midnight)
• The Word
• Depression helpline: 0800 111 757 (24-hour service)
• Rainbow Youth: (09) 376 4155
• CASPER Suicide Prevention
If it is an emergency and you feel like you or someone else is at risk, call 111.