The National Party is calling for an inquiry into the Crown's handling of the Jayden Meyer rape case after an appeal of a sentence of home detention failed.
Meanwhile, Justice Minister Kiri Allan has acknowledged the victims' bravery and highlighted the High Court found the sentence "wasn't what it should have been".
Meyer was sentenced in July to nine months of home detention for raping four 15-year-old girls and indecently assaulting another when he was 16. The sentence set off protests in a number of centres across New Zealand, with one person likening it to a "slap on the wrist".
Deputy Solicitor-General Madeleine Laracy appealed the sentence in the High Court.
In her judgment on the appeal this week, High Court Justice Fitzgerald said an appropriate sentence would have been imprisonment.
The Justice noted in her judgement that the Solicitor General had described the sentence as "manifestly inadequate". That's despite Crown prosecutors themselves endorsing home detention as appropriate.
However, while Justice Fitzgerald agreed the home detention sentence was "manifestly inadequate" and said the approach in the District Court was "irregular", she wrote that there were a number of "unique and unfortunate" factors for why she had to decline the appeal.
Those circumstances include that the appeal was filed late, Meyer is already three months into his nine-month sentence, and a change to imprisonment could risk "undermining progress to date in rehabilitation". Simply extending the home detention sentence would be "an affront to the victims", Justice Fitzgerald said.
In a statement on Friday, National's justice spokesperson Paul Goldsmith called for Justice Minister Kiri Allan to launch an inquiry into the Crown's handling of the case and its implications.
"Most New Zealanders are incensed by what the High Court called a 'manifestly inadequate' sentence for such serious crimes and the message it sends to victims of such crimes," he said.
Goldsmith wants an inquiry to consider why the Crown missed the deadline for appeal and why the Crown didn't initially seek a sentence of imprisonment.
"The inquiry should ask whether the sentencing regime gives too much scope for judges to reduce sentences," he said.
"It's fair to ask if a system that allows a judge to take what was generally agreed to be a crime that warranted an eight-year prison sentence down to nine months home detention is fundamentally too loose."
Allan told Newshub the victims "bravely came forward" to share their story and the High Court had found that "in these circumstances the penalty wasn't what it should have been".
"I just want to acknowledge that for those… young women they have gone above and beyond to share their experiences with all of us and these circumstances and situations should never happen again."
She explained that it is difficult for her to comment specifically on a case due to the separation of powers between the executive and the judiciary.
The Cabinet Manual says ministers "should not comment on the results of particular cases, on matters that are subject to suppression orders, or on any sentence handed down by a court". If a minister "has grounds for concern over a sentencing decision, the Attorney-General should be informed", it says.
"Ministers may comment on the effectiveness of the law, or about policies on punishment (that is, on matters where the executive has a proper involvement), but not where the performance of the courts is brought into question."
Allan said the High Court had found the system didn't perform "as it was meant to do". She doesn't want to see that cause other victims not to come forward.
"The last thing that we would like to see, that anybody in government or any New Zealander, would be that a victim is put off from coming forward to share their story and have somebody take accountability where they cause sexual violence and harms to victims."
Allan said that as Justice Minister she's responsible for ensuring the settings are fit for purpose in sentencing. In this case, she said the High Court had found the right settings were there, but they weren't applied correctly.
She has asked officials about the type of training the judiciary do to ensure "that they are appropriately equipped".
"They're always looking at refining the types of training that the judiciary has, and that's an important constitutional safeguard for us all."
Allan said the likes of Crown Law, the Solicitor-General, the Attorney-General and the courts "will be reflecting on how they can better improve the processes".
The Government has work underway to "enable better participation of victims of sexual harm and violence. to remove some of the procedural barriers".
Attorney-General David Parker told Newshub: "The High Court judgement and other related court documents that have been made public set out clearly what happened in this case."
"Any further response falls to the Solicitor-General in terms of her oversight of public prosecutions. I have asked her to look at whether anything further is required.”
The judgement from Justice Fitzgerald, released publicly this week, said the Solicitor-General became involved in the Meyer case a day after media reporting of the sentencing.
However, Laracy said the appeal was "not in response to the media and social outcry", Justice Fitzgerald noted in her judgement, but because "the Solicitor-General considered the sentence manifestly inadequate and requires correction".
Asked about the delay to appeal, Crown Law told Newshub on Friday that "there is no systemic issue of Crown delay".
"This was a rare situation."
The judgement shows that home detention was submitted by the Crown as the "most appropriate sentence".
The judge at sentencing, Christopher Harding, is said to have summarised the Crown's position on the sentence by saying: "The Crown submits at this stage that a sentence of imprisonment, despite that being the ordinary consequence and indeed one of many years, a sentence of imprisonment would not be appropriate and a sentence of home detention with judicial monitoring is the most appropriate sentence.
"They provide authorities for the proposition that ordinarily a substantial sentence of imprisonment is appropriate and they are undoubtedly correct."
Justice Fitzgerald said the District Court judge did not follow "orthodox sentencing" exercises when sentencing Meyer.
"The Judge did not elaborate on why he accepted the parties' submissions that a sentence of home detention was the appropriate outcome, despite his acceptance that a substantial sentence of imprisonment would ordinarily be imposed."
The High Court Justice said the sentencing "lacked transparency, which in turn undermines public confidence in the administration of justice".