The highest court has refused leave to a lobby group and two executives to challenge the validity of Northland Regional Council rates in Kaipara.
In April this year, the Court of Appeal overturned a lower court ruling that invalidated the rates after an appeal was filed by NRC.
In August last year, the High Court at Whangarei ruled in a judicial review proceeding that council rates collected in Kaipara between 2011 and 2016 were invalid but did not order a refund.
The application for judicial review was filed by the Mangawhai Ratepayers and Residents' Association, its chairman Bruce Rogan, and his wife Heather.
They decided to challenge the Court of Appeal ruling in the highest court, which refused leave, saying the criteria for leave to appeal had not been met.
One of their arguments was that rates should not have been set on a GST-inclusive basis and that penalties could not be charged on the GST added to rates.
The Supreme Court said the Court of Appeal and the High Court were correct to reject that argument.
The ruling means those who refused to pay the NRC rates in Kaipara will now have to pay them.