A lawyer for the Attorney-General has told a court the use of fluoride in water supplies is not a human rights issue.
The South Taranaki District Council is being challenged at a judicial review at the New Plymouth High Court over what it says is its statutory right to fluoridate water supplies in Waverley and Patea.
Christchurch-based New Health New Zealand is testing the authority of all councils to be able to add fluoride to water.
On Monday, its lawyer Lisa Hansen argued that the South Taranaki council is breaking the law and breaching the New Zealand Bill of Rights Act by adding the substance she said is akin to a medicine.
But Austin Powell, the lawyer for the Attorney-General, told the hearing on Tuesday that only direct interference with the body - such as inoculation or forced sterilisation - engages Section 11 of the Bill of Rights, which says everyone has the right to refuse to undergo any medical treatment.
Mr Powell said if the law was otherwise, it would give an individual an unwarranted power of veto over decisions made for the good of the community. He said adding fluoride is public health measure which is no different from adding chlorine to water to remove bacteria.
A lawyer for the council, Duncan Laing, said the decision to fluoridate Waverley and Patea followed a democratic decision-making process that falls within the Local Government Act and the Health Act. He argued that fluoridation is not a medical treatment and, therefore, cannot be breaching the Bill of Rights.
The council said teenagers living in South Taranaki have a far worse state of dental decay than in other parts of New Zealand.
Duncan Laing said 17-year-olds enrolled with the Patea dentist have, on average, eight to 10 decayed, missing and filled teeth compared with a nationwide teenage score of under two. He said there is a clear connection between fluoridating water and decreasing dental decay across the population.
New Health New Zealand lawyer Lisa Hansen earlier argued that the council has no regulatory power to add fluoride and to do so would require a law change. She questioned the validity of a Lower Hutt city ruling made 50 years ago, paving the way for councils to use it, and said the country is now in a different legal, scientific and social era.
The Attorney-General, the Taranaki District Health Board and the Ministry of Health are supporting the South Taranaki council with its defence and helping with court costs.
Justice Hansen reserved his decision on Tuesday.