A lawyer representing seven Red Devil gang members says police will struggle to overturn a court decision to stay the case against them in the wake of a fake arrest and prosecution.
A judge this week stopped a case against 21 members of the Nelson-based gang facing serious drugs and firearms charges because police faked the arrest and prosecution of an undercover officer.
Police say they are discussing legal options for an appeal against the stay of proceedings issued by the High Court in Nelson.
Deputy Police Commissioner Mike Bush say police seek the permission of the judiciary in undercover cases, and officers did so in the Nelson operation, but he accepts they did not tell the judge enough. He says police always take legal advice in this type of operation.
But lawyer Steve Rollo told Radio New Zealand's Morning Report the CIB national manager acknowledged in the High Court that police had never taken legal advice and did not get permission from the district court judge.
Mr Rollo said a judge would never have been able to give permission for actions such as arresting someone on a false allegation, and there is no suggestion this occurred.
In further fallout from the botched operation, the lawyer for a former president of the Hell's Angels in Auckland, Philip Schubert, says a drug charge against him is likely to be stayed.
Law professor Warren Brookbanks says he expects other criminal cases may have to be stopped by the courts.
In the Nelson case, police in May 2010 set up a fake drug bust using a fake search warrant to arrest an undercover officer, in order to allay the suspicion of members of the Red Devils gang he had infiltrated.
Police told the Chief District Court Judge some details about the operation, but the information was never passed to the presiding judge.
The High Court at Nelson subsequently found police actions over the fake prosecution were in breach of the court process, and stayed proceedings.
Criminal Bar Association president Tony Bouchier says bringing the judiciary into police investigations in this way is anti-democratic and needs an independent investigation.