A senior Hells Angel is trying to get a drug charge dropped because of a fake police prosecution of an undercover officer.
Philip Ernest Schubert, a former president of the Mt Eden chapter of the motorcycle gang, was charged with offering to supply methamphetamine after a covert police sting.
He was arrested as part of an 18-month inquiry in which an undercover officer infiltrated the Red Devils in Nelson, recognised as a feeder gang to the Hells Angels.
But a deal struck between senior police and the chief district court judge to allow the officer to be arrested in a bid to protect his assumed identity and "ensure his continued safety, divert suspicion and enhance the appearance of criminality" is now the subject of a legal challenge.
The police asked the permission of Judge Russell Johnson for the prosecution of Michael Wiremu Wilson to go ahead, as the undercover agent would have a complete defence under the law.