The Northland Regional Council isn't ruling out an appeal after the High Court quashed years of Kaipara rates.
In the dispute spanning more than six years, as many as 1000 ratepayers refused to pay in protest at ballooning debt levels and the council's failure to disclose its borrowing to fund the Mangawhai wastewater scheme.
Justice Ailsa Duffy has now ruled the rates levied by the Northland Regional Council via the Kaipara District Council rate demands were invalid.
The regional council's chairman, Bill Shepherd, said the ruling threw up a number of important issues, as well as lessons to be learned.
He said the council was now carefully considering the judgement and its options, including whether to appeal.
Mr Shepherd said the decision also had potential implications for other councils and it was already seeking a law change to clarify how it could set its rates.
The district's mayor, Greg Gent, said the council was still absorbing the ruling.
"The rates are quashed, we're not even sure at this point actually what that means cause it's non-specific, so there's a bit to work through around this one.
"The sad thing is that it's all very technical, it's going to cost Northland ratepayers a lot of money, and I'm not sure for what."
Mr Gent said it would also impact other councils around the country.
The regional council isn't ruling out an appeal.