The country's highest court has dismissed an appeal by two men associated with a motorbike gang infiltrated by undercover police.
The appeal followed an 2009 police investigation into links between the Red Devils Motorcycle Club and the Hells Angels.
In the course of the investigation, two undercover police officers infiltrated the Red Devils.
When suspicion developed about one of them, known in the gang as Michael Wiremu Wilson, the police took steps to strengthen his credibility.
A fake search warrant, which on its face appeared to have been issued by a court official, was prepared and "executed".
Police also prepared and filed criminal proceedings, involving fake charges, against the undercover officer, who was arrested and appeared in court.
As a result of evidence gathered during the operation 21 associates of the Red Devils were charged with a range of offences, totalling 151 charges.
Once the police actions to conceal the undercover officer became known, those accused applied to the High Court for a stay of all charges on the ground they were so contrary to proper and acceptable police practice that they amounted to an abuse of the courts' process.
In the High Court, Justice Simon France said he believed police thought they were acting legitimately, but said there was fundamental and serious abuse of the court's processes by the police. The charges were subsequently halted.
The Crown then successfully appealed Justice France's decision to the Court of Appeal.
Two of the men charged, Terry Jones and Mark Lee, then applied for leave to appeal at the Supreme Court.
However, in a decision released from the Supreme Court today, Justice John McGrath said the court had no jurisdiction to give the applicants leave to appeal against the Court of Appeal judgment.
Their application was subsequently dismissed.