Cure Kids' latest State of Child Health Report has revealed worsening health trends and shocking inequities.
And in response to the report, the Children's Commissioner Judge Frances Eivers said "almost one-third of our mokopuna bear the brunt of health conditions".
"On many measures, New Zealand is currently one of the worst places in the developed world to be a child," she added.
Cure Kids CEO Frances Benge told Newshub that too many children are being admitted to the hospital when it could have been avoided.
"We've got 40,000 kids a year being admitted to hospital for completely preventable illnesses."
Rheumatic fever is one of them, and it's only when you see the figures you realise just how startling the inequities are.
"I find it totally shocking that Pacific Island kids are 140 times more likely to be admitted to hospital with acute rheumatic fever," said child health researcher Dr Christine McIntosh.
That's 140 times for Pacific Island kids and for Māori it's 50 times.
"So this is an absolute disgrace really for a beautiful country like New Zealand which has great standards of living. For some that's not the case," Benge said.
But it's respiratory conditions causing the most hospital admissions, and the rate of hospitalisations for children with serious dental decay has steadily increased.
The report found that "those living in the most deprived areas had three times the number of tooth extractions".
Dr McIntosh said better access to primary care would help but there is no simple fix.
"What we can see when we read the report is the effects of child poverty and I think that addressing child poverty would be the most important thing."
And the childhood health problems can have lifelong impacts, and more research is crucial.
"So that we understand how to make all children have that opportunity for a healthy and well life," said Dr Mclntosh.
Cure Kids is already working on next year's report which will include the mental health of young people.