The courts in sentencing pursuant to N.J.S. 2C:43-5 shall not fix or limit the duration of sentence, but the time which any person shall serve in confinement or on parole shall not in any case exceed 5 years or the maximum term provided by law for the crime for which the prisoner was convicted and sentenced, if such maximum be less than 5 years; provided, however, that the court, in its discretion, for good cause shown, may impose a sentence greater than 5 years, but in no case greater than the maximum provided by law, and the commitment shall specify in every case the maximum of the sentence so imposed.
N.J.S. § 30:4-148