Local Government NZ, which represents councils, has welcomed the move and says fluoridation is an important health decision best made by experts.

Health Minister Jonathan Coleman says New Zealand has high rates of preventable tooth decay and fluoridated water will improve oral health and mean fewer costly trips to the dentist.

“The change could benefit over 1.4 million New Zealanders who live in places where networked community water supplies are not currently fluoridated,” he said today.

“Moving the decision-making process from local councils to DHBs is recognition that water fluoridation is a health-related issue.”

Fluoridation is a controversial issue and has run into strong opposition in some communities.

In South Taranaki it ended up in court, where the council’s authority to add fluoride was tested.

Dr Coleman says it makes sense for DHBs to make the decisions.

“Water fluoridation has been endorsed by the World Health Organisation and other international health authorities as the most effective public health measure for the prevention of dental decay,” he said in a joint statement with Associate Health Minister Peter Dunne.

About 2.3 million people currently have access to fluoridated water.

It occurs naturally in water supplies, but New Zealand levels are low compared with other countries.

Local Government NZ president, Lawrence Yule, says assessing claims about the value of fluoride and its potential harm falls outside the expertise and experience of local authorities.

“In recent years, many councils have had their decisions to fluoridate water supplies challenged in court, creating unnecessary costs for ratepayers and uncertainty for the councils themselves,” he said.

In 2014 Prime Minister John Key’s chief science adviser, Sir Peter Gluckman, and the Royal Society of New Zealand, concluded there was “compelling evidence” that fluoridation produced broad benefits for dental health.

In 2013, more than 40 per cent of all five-year-olds and more than 60 per cent of Maori and Pacific five-year-olds had already experienced tooth decay.

Dr Coleman expects to introduce a bill to parliament later this year.