A test case that could determine the fate of a number of defaulting Mangawhai ratepayers has wrapped up at the Whangarei District Court.

The Kaipara District Council is suing the ratepayers chairman Bruce Rogan for 22,000 in back rates and penalties.

He's the first of around 100 defaulting ratepayers being taken to court who've been withholding since 2012 in protest after the council borrowed for a sewage scheme without telling them.

In his final submissions today the defendants' lawyer Jeremy Browne told Judge de Ridder the council could not force Mr Rogan to pay because its rate demands were full of errors.

But council lawyer, David Neutze accuses them of nit-picking policies and believes rates validation should be a matter for the high court.

Judge de Ridder told the court he'll need some time to go through both cases before he can deliberate.