Prosecutors have failed in an attempt to have the sentence imposed on a Canberra nightclub killer extended, with the murderer's barrister providing "a blow-by-blow refutation" of the appeal.
Frederick Elijah Mercy Tuifua, 28, murdered Comanchero bikie boss Pitasoni Tali Ulavalu, 48, by stabbing him in the neck during a brawl at Civic nightclub Kokomo's in July 2020.
The self-described "coward" and former Canberra Grammar School student, who pleaded guilty, also admitted intentionally inflicting grievous bodily harm on another bikie by knifing him in the leg.
Justice Michael Elkaim sentenced the killer to 20 years in jail for those offences and an unrelated prison assault, which involved Tuifua and four others bashing a man they wrongly believed was a paedophile.
The judge imposed a 10-year non-parole period, but the sentence was structured in a way that required Tuifua to in fact serve a minimum of 11 years before becoming eligible for release.
Director of Public Prosecutions Shane Drumgold SC challenged the sentences relating to the nightclub offences last November, telling the ACT Court of Appeal the punishment was "manifestly inadequate".
"It is clearly disproportionate and will lead to some concerning precedents," Mr Drumgold told the court.
"The nature of the offending is not represented in the ultimate sentence that's imposed."
Tuifua's barrister, Bret Walker SC, responded by arguing the appeal should be dismissed.
He said the key question for the appeal court was whether the punishment imposed on Tuifua had fallen outside an acceptable sentencing range.
Mr Walker compared his contrite client to remorseless Tinder date killer Jayscen Newby, who received a 24-year jail sentence in a case he labelled "atrocious", as he argued the answer was "very loudly, no".
In a unanimous decision to dismiss Mr Drumgold's challenge on Wednesday, three appeal court judges said Mr Walker's submissions had delivered "a blow-by-blow refutation" of the prosecutor's arguments.
"In the final result, the [prosecution] argument does not rise higher than a complaint that the sentence was not heavy enough as a value judgement," Chief Justice Lucy McCallum, Justice David Mossop and Justice Robert Bromwich said.
"The sentence was not, in all the circumstances, shown to be inadequate, let alone manifestly so."
The trio acknowledged that they were dealing with "an undoubtedly tragic set of circumstances".
"The offences were brutal and inexplicable, or at least not explained on the material that was before the sentencing judge," the appeal court said.
"On the limited available evidence, despite the disturbing nature of the attack ... the offences were not shown to be pre-planned, targeted or reflective of an inherently or irredeemably evil state of mind.
"The evidence before [Justice Elkaim] made it clear that the murder has devastated and ruined the lives of the family and friends of the deceased, Mr Ulavalu, especially his wife and child born afterwards."
The appeal judges also noted that the lack of any cogent explanation for Tuifua's actions at Kokomo's gave rise to legitimate concerns the promise of his rehabilitation may prove "illusory".
While they recognised the safety of the community may prove a barrier to Tuifua's release when his non-parole period finished, the trio said that would be a matter for the Sentence Administration Board.
Tuifua will become eligible for parole in August 2031.
