Police are appealing a High Court decision to throw out charges against 21 Nelson gang members after police tried to falsely prosecute an undercover officer to boost his credibility within the group.
Last week Justice Simon France ordered a stay of proceedings against the group, who were facing a range of charges including drug offences and being part of an organised criminal group.
The Solicitor General confirmed today that the decision would be appealed.
Police were investigating the emerging Red Devils Motorcycle Club, who they suspected were about to become a chapter of the Hells Angels.
During a crackdown, dubbed Operation Explorer, police bosses became concerned that an undercover officer known in the gang as Michael Wiremu Wilson was about to be exposed.