Councils vulnerable to activist lobbying are pushing for the Ministry of Health to take over decision-making powers on the future of water fluoridation.

The current Health (Fluoridation of Drinking Water) Amendment Bill before Parliament proposes to take the decision to fluoridate away from councils and give it to district health boards (DHBs).

But at a select committee hearing on the bill this week, Hutt City Council, South Taranaki District Council, and Hamilton City Council urged politicians to hand fluoridation decisions to the director-general of health, in a move that could mean one nationwide rule on fluoridation.

DHBs, just like councils, were vulnerable to pressure from anti-fluoridation lobbyists, activists and "armchair experts", South Taranaki chief executive Craig Stevenson told the committee.

The issue was "highly vexed, very divisive" and costly. Stevenson said a controversial legal battle to fluoridate the water supply in Patea and Waverley had cost $320,000 so far.

Masterton is among several towns and cities to offer residents the option of a fluoride-free tap.

In October last year the council won a four-year court battle for the right to fluoridate the supplies. But, in February that ruling was put in doubt when the Supreme Court granted lobby group New Health New Zealand the right to appeal.

He applauded the Government's move to put decisions around fluoridation into the hands of health professionals, but said the bill did not go far enough, and decision-making powers needed to be elevated to a national level.

Hamilton councillor Dave Macpherson said he had seen the city split over fluoridation many times. In 2013 the city council voted to go fluoride-free, then in 2014 voted to refluoridate.

He did not think DHBs were set up to cope with the "inordinate amount of time" involved in the consultation process, given their primary concern was delivering public health.

"They're not there to handle big debates," Macpherson said.

He wanted to see a provision to ensure non-fluoridated water sources were available, as Hamilton had done at two sites in the city last year.

Lower Hutt mayor Ray Wallace also supported a national approach, but said it should be able to recognise local wishes, such as those in the old borough of Petone.

There was an outcry in the 1990s when the council suggested adding fluoride to Petone's water, although today Wallace suspected the community would be split 50/50 on the issue.

"This is an extremely emotive decision, and councils are not geared to make medical decisions," he said.

Anti-fluoride submitters claimed fluoridated water was a neurotoxic health risk, and fluoridation should be an individual choice.

Hope International's Evan Sadler said the ministry was covering up facts, was being controlled by vested interests, and that the health fallout around fluoride would one day dwarf the thalidomide drug scandal.

Health Minister Jonathan Coleman said the Government had "got the settings about right" when asked about the councils' recommendation to get the bill extended to a national approach beyond the remit of DHBs.

A report is due on the bill in June. - Stuff