Lisa Preston is one of the lawyers representing Brown, who was one of two people convicted of murdering 19-year-old Jack McAllister in Invercargill, in 2017.
Preston told the court that young people should face a finite term of imprisonment instead of life, noting that parole post-release is the "distinguishing feature" of a life sentence.
She said "living under the constraints of parole" had a "significantly greater" impact on the life of someone released after 10 years aged 30, rather than someone released after 10 years aged 70.
A finite term could give youth more of a sense about their future, Preston said.
She also noted that the shame of being convicted of murder would never leave a person.
"Where a life term is imposed to mark that offending, that record of life imprisonment and the continued oversight of the involvement of the state in your life post-release involves impacts on both your prospects to obtain work and, certainly if you are lucky to obtain work, sometimes on the conduct of your work."
However, aspects of this were questioned by the panel of justices presiding over the hearing, including Justice Collins, asking how to work out "that a finite sentence is going to be more conducive towards a young person's rehabilitation and adaption than, say, a life sentence with an MPI [minimum period of imprisonment] of 10 years".
Preston admitted there was not as much research around this as they would like.
Her colleague, Fiona Guy Kidd, also representing Brown, told the court there had been finite cases for murder convictions.
She went on to argue that her client should have a sentence of 9-10 years and that it should be without a minimum period, meaning Brown would be eligible for parole after serving a third of his sentence.
"The community will be adequately protected by the Parole Board carefully considering whether he is an undue risk to society when he becomes eligible, and directing and ensuring that appropriate treatment is engaged," Guy Kidd said.
One of Epiha's lawyers, Tim Conder, told the court it had become clear since the Sentencing Act 2002 passed through Parliament that life sentences for young people were unjust in some cases.
He said it was important to identify not only if it was unjust to sentence an offender to life when all circumstances are considered, but also whether the murder - focusing on the offence itself - "was of the kind that Parliament expected to receive a life sentence".
Epiha, who stabbed Maree Nathan to death at a Christchurch house party in 2017, was the only appellant present for the hearing, watching via audio-visual link.
The hearing is set to continue.
- RNZ
