Director-General of Health Dr Ashley Bloomfield has told 14 local councils to start fluoridating their drinking water supplies, which will bring the number of New Zealanders drinking fluoridated water up to 60 percent.
And Nelson's one of a number of councils that don't add fluoride to its drinking water, but that's about to change.
"Today I've written to 14 local authorities, directing them to fluoridate their drinking water supply," Dr Bloomfield said on Wednesday.
It's the first time Dr Bloomfield's issued such a directive since fluoride decisions were transferred from councils to him.
The Dental Association's Rob Beaglehole is overjoyed, calling the move a "game changer".
"We know that kids living in fluoridated areas have a 40 percent less chance of tooth decay than those living in non-fluoridated areas."
Fourteen councils across the motu have up to three years to add fluoride, and in Nelson the views amongst locals are mixed.
"I'm against fluoride in the water," said one
"I'm absolutely against it."
"Fluoride's not a bad thing, nevertheless dentists say it's supposed to help your teeth, that's what I reckon," said another.
Only 13 councils currently have fully fluoridated water supplies, while 54 councils are either fluoridating some supplies or none altogether.
As Aotearoa moves towards a national approach to fluoridation, Dr Bloomfield's written to those councils to tell them they're next.
"Made it very clear to them that we will be following up with them and look to fluoridate their water in the near future."
Fluoride can be controversial, with Fluoride Free NZ's Lawrie Brett raising health concerns.
"The procedure is not effective, the ministry and the Government at large is ignoring the current world research."
But public health expert Professor Murray Thomson told Newshub there is no harm.
"There's no evidence for any ill effects of it. You'd have to go up to hundreds of parts per million for there to be any measurable effects."
Dentists hope to see the positive effects of fluoride in the coming years.