The ruling stems from the case of Donald Boutilier who pleaded guilty in May 2012 to offences including assault and robbery.
His lawyer challenged the Crown's bid to declare him a dangerous offender, based on a Conservative omnibus crime bill that was passed in 2008.
A judge sided with Boutilier's lawyer and in late May gave the government one year to fix the law by rewriting a portion of the Criminal Code so that it no longer violates the charter.
The province's Criminal Justice Branch has announced it will fight the judge's decision.
It argues the judge made errors of law, and without those errors, a different ruling may have been made, and therefore a challenge is in the public interest.