One of the people found guilty of attacking a young woman who was later found unconscious and nearly dead in the Dome Valley is appealing one of her convictions, and her 16-year prison sentence.

Julie-Ann Torrance was convicted in 2017 for her role in the brutal assault and attempted murder of the 19-year-old victim.

She and her co-offender, Nicola Jones, laughed and egged on co-accused Wayne Blackett as he unsuccessfully tried to snap the victim's neck in May 2016.

Blackett next hit the woman repeatedly in the head with a hammer before she was left for dead on a roadside north of Auckland.

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Torrance was found guilty after a trial in the High Court at Auckland for sexually violating, assaulting, robbing and kidnapping the victim in two separate attacks.

She was sentenced to 16 years and seven months in prison, but is today appealing the sexual violation conviction and the sentence.

Her case was heard in the Court of Appeal in Wellington this morning, where her lawyer, Chris Tennet, said the jury returned inconsistent verdicts on the sexual violation charge.

Torrance was found guilty while her co-accused was found not guilty on the charge.

Tennet also argued more of a discount should have been allowed in sentencing to factor in Torrance's mental health issues, and her grief and PTSD following the suicide of her daughter.

Her anger towards the victim was fueled by the belief the victim had stolen some items belonging to Torrance's dead daughter.

But Crown lawyer Simon Barr said the "generous" starting point adopted by the sentencing judge "absorbed" any extra discount she should have received.

He said the mental health issues explained her anger towards the victim, but could not explain the irrational actions she took.

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He also said the accounts put to the jury on the sexual violation charge still allowed for Torrance to be found guilty on it if Jones was found not guilty.

During the trial, the court heard the attacks started after Jones became angry with the young woman because she believed the woman had slept with her partner.

Then in April 2016, the young woman was lured to a former friend's Newmarket flat under the false pretence of a drug deal.

There Jones and Torrance ambushed, bashed and tasered the woman before threatening to repeat the attack if she did not leave Auckland for good.

One month later, Jones and Torrance, along with two others already sentenced to prison terms - Michelle Blom and Jaclyn Keates - kidnapped the woman from near Karangahape Rd and took her to Blom's west Auckland home.

There she was bashed with a cricket wicket and bat and sexually violated.

After being held captive for about 22 hours, Jones, Torrance and Blackett drove to Conical Peak Rd with the young woman tied, wrapped in a tarp and thrown into the back of a Hilux ute.

After trying to strangle the woman, Blackett took a hammer and delivered at least 10 blows to the woman's head, causing multiple fractures and depressing her brain by 2cm, prosecutors said.

The Court of Appeal has reserved its decision.