The High Court has refused to grant a request to stop the Hamilton City Council reintroducing fluoride into its water supply before a judicial review on the issue can be heard in September.
Safer Water Alternative New Zealand (SWANZ) asked for the interim order in the High Court at Hamilton on Thursday to stop the council reintroducing fluoride.
The council stopped adding fluoride to the water supply in June last year but decided to bring it back after a referendum in October last year voted in favour of it.
It wanted to put it back immediately - a move which prompted SWANZ to take court action.
SWANZ said if the council was allowed to reintroduce fluoride, it would give it an advantage when the full court hearing was heard.
But Justice Kos said SWANZ's case for a judicial review would not be prejudiced by his decision.
The Hamilton City Council intends resuming fluoridation within a week.