The question of whether or not a Supreme Court Judge was biased in his handling of a case is being considered by the Court.
The case has been brought by the Saxmere wool growers group, which is seeking substantial compensation from the former Wool Board, which refused to provide the company with funds for marketing.
The High Court ruled in Saxmere's favour, but in 2007 the Court of Appeal overturned that decision and the Supreme Court then turned down Saxmere's application for a further appeal.
Saxmere is now arguing that one of the Supreme Court Judges, Justice Bill Wilson may have had a conflict of interest because he co-owned a horse stud with one of the Wool Board's lawyers.
Saxmere's lawyer told the Supreme Court on Tuesday that impartiality is a defining feature of judicial power and fundamental to the rule of law in New Zealand.
Lawyers for the Wool Board are still to present their submissions.