The Crown Law Office says the Solicitor-General will not appeal against the sentence imposed on the killer of Liberty Templeman.
The 15-year-old was murdered in November 2008 by Kerikeri schoolmate Theo Kriel, aged 14.
Kriel, now 16, was sentenced in the High Court in Whangarei in March this year to life in prison with a non-parole period of 11-and-a-half years.
Miss Templeman's parents protested, calling the sentence a farce.
The longest non-parole period available to the court was 17 years. Northland Crown prosecutor Mike Smith asked Solicitor-General David Collins to consider an appeal in the hope of a longer non-parole period.
A spokesperson for Crown Law says senior counsel who debated and reviewed the sentence found the judge acted within his discretion and there were no discernible grounds for appeal.