But the Fluoride Action Network New Zealand, which has been putting other research forward, claims fluoride is harmful and linked to arthritis, cancer, thyroid dysfunction, lowered IQ and hypersensitivity.
National co-ordinator Mary Byrne said the group has been buoyed by Hamilton's decision and was now looking to lobby other major councils including Auckland and Wellington.
Emmeline Haymes, co-ordinator of the National Fluoridation Information Service, which reviews scientific research on fluoridation, said the service specification of DHBs was also mostly voluntary.
"In my work with DHBs, it would be fair to say that none of them are having proactive advocacy going on."
Instead, DHBs reacted when councils were being lobbied by anti-fluoride groups and approached them for scientific advice, she said.
"So they tend to be very much reactive and on the back foot.
"There is no co-ordinated national approach to advocacy, and the ministry certainly at present doesn't appear to have the numbers of people or resources to do the advocacy itself."
Otago University dentistry lecturer Dr Jonathan Broadbent felt there was no longer any scientific debate over whether fluoride was safe and effective.
A recent survey published in the New Zealand Dental Journal found that 93.5 per cent of dental practitioners supported community water fluoridation, while the rest were either unsure or against it.
The Royal Society of New Zealand also recently looked at a scientific review of fluoridation but found there was no new information to warrant one.
Dr Broadbent said to a certain extent, there had been a hands-off approach by DHBs for a long time.
"Where councils are failing their populations and going against what their populations are telling them, maybe that's where central Government needs to get involved."
New Zealand Dental Association president Dr Geoff Lingard suggested legislation around local authorities could be strengthened, or that authority be handed to DHBs.
"There may be other alternatives, but at the moment they haven't been explored."
He believed the establishment of a Government-led advocacy body, which some had called for, would be an improvement.
The offices of Health Minister Tony Ryall and Associate Health Minister Tariana Turia were yesterday still referring comment on to the ministry.
Dr Pat Tuohy, chief adviser on child and youth health, said the ministry was "confident" that DHBs were strong voices for fluoridation in their local areas.
"Nevertheless in light of the recent Hamilton City Council decision, the ministry will be reconsidering how best to support DHBs, councils and local communities in this area," he said.
"The ministry position is that local councils are appropriate bodies to make such decisions, as indeed they are the appropriate bodies for making a range of other health-related decisions within their areas.
"However we would urge councils to consider how the voices of those groups within their population with the most to gain from the retention of fluoride in the water are heard when decisions are made."
Twenty-two out of New Zealand's 67 councils, including Wellington, Auckland and Dunedin, add fluoride to their water.
Christchurch, Whangarei, Tauranga, Rotorua, Napier, Wanganui, Nelson, Timaru and Greymouth have never fluoridated their water, and New Plymouth also decided to stop.
The debate is expected to roll on later this year when Hastings and Whakatane hold referenda.
