Putting fluoride in all of New Zealand's water will go a long way to preventing tooth decay, Associate Health Minister Dr Ayesha Verrall says.
She told The AM Show on Friday half of New Zealand's water is already fluoridated - but new legislation will put the power in the Government's hands to finish the job.
If the legislation is passed through Parliament it will allow the Director-General of Health to fluoridate the water. Dr Verrall says she expects it will be in place from March 2022 - but as nothing is set in stone she "isn't celebrating yet".
Currently local councils control whether or not the water is fluoridated.
"I really want an approach that's going to be effective," Dr Verrall said.
"We need to make sure we're protecting the children."
Tooth decay is one of the leading causes of preventable hospitalisations for children in New Zealand.
Dr Verrall says it's "heartbreaking".
"Because they're so little they can't have the procedure awake so they end up having a general anaesthetic for preventable tooth decay."
Professor Barry Borman, the director of environmental health indicators New Zealand, says it's "about time" fluoride was introduced across Aotearoa.
"This should have happened years ago. We've seen the consequences of the delay in this legislation, with oral health the way that it is, particularly for children."
He acknowledged there would be pushback against the idea as fluoride has long been a controversial subject.
"Anti-fluoridation advocates are going to be opposed to this. But nobody has really put up epidemiologically sound evidence to support their views."
Fluoride is a naturally occuring substance that works in three ways to protect teeth.
It makes teeth more resistant to decay by strengthening the tooth surface, interferes with the growth of the bacteria which cause cavities and helps to repair the early stages of tooth decay.
Opposition to fluoridation has existed since the 1940s when conspiracy theorists claimed it was a communist plot to undermine the American health system.
However international health industries such as the Centre for Disease Control and Prevention, the New Zealand Medical Association and the American Public Health Association have consistently supported fluoridation, saying there is no link between any adverse health effects and exposure to fluoride in drinking water.