Hill, now 49, was jailed for a maximum of 23 years and six months, with a non-parole period of 17 years in Newcastle District Court in December after he pleaded guilty to aggravated kidnapping and a string of aggravated sexual assault offences.

It was a crime that shocked the Hunter; a young girl is abducted in broad daylight, held for five hours and driven to a number of bush locations where she is subjected to depraved sexual acts.

It is rare for the Office of the Director of Public Prosecution (DPP) to appeal against the inadequacy of a sentence as long as the one Hill received.

But it was the "profoundly grave conduct" and the effect on the young girl that prompted the DPP to label the sentence "manifestly inadequate" and tell the Court of Criminal Appeal that it was "simply too light" and it would be an "affront to the administration of justice" if the state's highest appellate court did not intervene.

"When one looks at the profoundly grave conduct, the effect on the victim and the absence of mitigating factors.... [the sentence] is too low and erroneously so," Deputy Director of Public Prosecutions Huw Baker, SC, last month told a three-judge bench of the CCA.

"[The DPP] would say the court has to intervene because it would be an affront to the administration of justice to allow for a sentence that is this erroneously lenient to remain."

But the CCA disagreed and dismissed the appeal in a judgment on Monday morning, ruling that while the sentence could be regarded as lenient, it was not "manifestly inadequate", the hurdle for a prosecution inadequacy appeal.

The CCA also dismissed prosecution claims that the aggregate sentence was afforded too large a degree of concurrency.

The ruling means Hill's sentence stands and he will not be eligible for parole until 2035 at the age of 64.

Hill has lodged a notice of intention to appeal against the severity of his sentence, intending to claim it was "manifestly excessive", but the appeal is yet to be filed.