Dental experts are calling for urgent change to the dental care system for children.
A new paper says a multi-service approach was necessary to address the long waits being imposed on children with severe decay.
University of Otago researcher Dorothy Boyd said it wasn't acceptable that children were experiencing preventable pain every day.
"We need to say, 'actually it's not okay that so many of our children can't chew, can't sleep, can't eat, can't play, because their teeth hurt'."
The oral healthcare workforce was severely understaffed, which had been exacerbated by Covid-19, she said.
"People are working really hard and feeling like they just can't keep up with the demand."
The problem overlaps with a variety of health issues, Boyd said.
She wants the government, healthcare industry and the public to contribute to the solution.
"It can't just be left to oral health services to prevent tooth decay. We need society to jump on board."
Good starting points were improving affordability of healthy food, fluoride toothpaste and toothbrushes.
The advertising industry also needed closer regulation to prevent targeted promotion of unhealthy foods to children, Boyd said.
"You just take a walk down the supermarket isle and you have a look at where the cartoon characters are, or where the sports characters are, and they're not on the healthy foods," she said.
"I think we need to regulate our advertising in a much greater way that protects our children from harm."
Māori and Pasifika children were more at risk of decay, Boyd said.
By the age of five, 60 percent of Māori and 70 percent of Pasifika children had already experienced tooth decay, as opposed to 33 percent of non-Māori or Pasifika children.