Dozens of young people under 16 referred for medical help, figures show.
Nine children - all aged under 10 - have been admitted to hospitals over the past few years for alcohol overdoses.
The shameful statistic is revealed in figures the Herald on Sunday obtained under the Official Information Act and does not include a 9-year-old boy who was filmed in a Hamilton skatepark this year.
A leading emergency doctor says the figures represent only a tiny percentage of underage drinkers.
Three people have been charged with supplying the Hamilton boy with alcohol after footage was posted on YouTube showing him stumbling and slurring his words. Police later said he drank eight cans of 7 per cent bourbon RTDs. The accuseds, in their 20s, have pleaded not guilty and will return to court tomorrow.
The boy did not need hospital treatment, but district health board figures for the past three years show dozens of other under-16s did. The youngest were three 1-year-olds in the Nelson-Marlborough and Waitemata districts, and others included a 3-year-old in the southernmost district, 5 and 8-year-olds in Canterbury and a 9-year-old in Waitemata.
Wellington Hospital emergency medicine specialist Dr Paul Quigley said only one in 10 underage drinkers came to hospital attention.
"There's a big group we miss because they are drinking at home, in their communities. All the figures you have - multiply them up."
As well as posing a higher risk of death when alcohol is poured into a small body, underage drinking increased the risk of early-onset dementia and cancer. Quigley said hours of trade should be reduced and prices increased at off-licences, and anyone convicted of supplying alcohol to minors forced to do drug and alcohol education.
Mirror Services director Deb Fraser said her counsellors dealt with 13-year-olds, but some said their substance abuse started earlier.
Drug Foundation executive director Ross Bell said the Sale and Supply of Alcohol Act should be tougher on those who supplied to children, as opposed to those just under the legal drinking age. The maximum penalty is a $2000 fine.
Life outlook after addictions 'awesome'
Aston Smith's alcohol addiction started with beer pinched from around the house when he was a 10-year-old.
But it didn't work fast enough for an impatient little boy who wanted to be just like his dad.
Smith, now 47, said he drank to get wasted.
"I remember taking that first drink and thinking it was the missing link for me. My first paralytic experience was at the age of 11. I drank Captain Morgan [rum] straight and woke up on a stranger's couch.
"I can't believe I'm still alive. I should have died 20 times over."
By 15 Smith was drinking every day. Only a few months after getting his driver's licence he racked up his first drink-driving conviction. His breath-alcohol level was 1023mcg - more than 2 times the current adult limit.
He was behind bars by 20. His rap sheet runs three pages long. Almost all of his 40-plus convictions were alcohol related, he said. That addiction spread to pills and meth, before he quit drink and drugs at 37.
As well as helping others as a co-director at Auckland drug and alcohol treatment centre Capri Hospital, Smith will marry his long-time partner next month, and has a 2-year-old daughter.
None of that would have been possible before he went clean, he said. "Life's awesome now."