A High Court judge has allowed the Crown's bid to appeal a decision in the high-profile Red Devils case.

In a judgement released tonight, Justice Simon France has referred the matter to the Court of Appeal.

He ruled that the issue of whether he erred in throwing out charges against 21 people after a police undercover operation was a question of law that should go to the higher court.

Defence counsel had argued it was not a question of law.

The decision followed a hearing in the High Court in Nelson today.

In October  Justice France strongly criticised police for a number of actions in Operation Explorer that involved an undercover police officer infiltrating the Nelson-based Red Devils motorcyle club.

The officer was arrested on fake charges, designed to boost his criminal credentials.

Justice France said the police had abused the court process, and issued a stay of prosecution in the case.

The Crown today argued that Justice France was wrong to issue a stay of proceedings against all 21.

Crown prosecutor Mark O'Donoghue said it was not appealing Justice France's decision on any of his findings of fact or circumstance, but whether the continuation of the prosecutions of the 21 would be an abuse of process.

"The Crown does not accept that continuing the criminal proceedings against those 21 defendants constitutes an abuse of process."

Defence lawyer Tony Bamford said the Crown's question was not a question of law and was too broad.

Defence lawyer Steven Rollo said the Crown was unable to question Justice France's decision with a question of fact or law and was now "hedging any which way".

The Crown could not find fault with Justice France's reasoning or his use of the law, so they were stuck with impugning the result with very little grounds, he said.

- © Fairfax NZ News