A 23-year-old murderer who brutally gunned down a mother-of-two has been sentenced to life in prison.

Turiarangi Tai appeared for sentencing this morning before Justice Matthew Muir in the High Court at Auckland after a jury found him guilty of murder in March.

He had already pleaded guilty to unlawful possession of a firearm.

Tai killed his partner Chozyn Koroheke with a shotgun burst at close range - no more than 50cm away - on a rainy April 4 night in Pakuranga Heights last year.

The 22-year-old's death was the tragic end to a series of brutal domestic violence incidents during the pair's volatile relationship, which included Tai hitting Koroheke in the head with a rock and stabbing her in the thigh.

The shooting came after another violent barrage by Tai against Koroheke.

Justice Muir said it was a sad indictment on New Zealand society and its shocking domestic violence record that the "circumstances [Koroheke] found herself in were far from unique".

The judge considered sending Tai to prison without the possibility of parole, which would have been the first instance of its kind for an offender with two strikes in New Zealand's legal history, the court heard.

However, he gave Tai a minimum period of imprisonment of 17 years. Tai will be 40 by the time he can seek parole.

Justice Muir called Tai a recidivist "seasoned" violent offender and "cowardly thug" and said it may take a "personal epiphany" if he is to reform behind bars.

He said Koroheke was a "strong, beautiful Māori wahine" pushed into a corner by a man wielding a loaded 12-gauge double barrel shotgun.

After the shooting - in which a single cartridge from shotgun tore through the right side of Koroheke's abdomen - Tai went on the run after attempting to stop Koroheke's blood loss.

It was a desperate attempt to evade police.

Paramedics were called to the home, which Tai and Koroheke were living in with Koroheke's brother and his partner and another flatmate, but the young mum was pronounced dead in the back of an ambulance.

Tai eventually handed himself in about two weeks later.

Tai's co-defendant, whose identity is suppressed, was charged with being an accessory after the fact to murder.

The jury found her not guilty of helping the fugitive when he was on the run.

Today, Koroheke's father, Jason Koroheke gave an emotional statement to the court as a downcast Tai avoided eye contact and looked towards his feet throughout the speech.

Jason Koroheke said his daughter, his "baby and princess", will now watch in spirit only as her two children go to school, get married and have children of their own.

Jason Koroheke said Tai had "absolutely no remorse" and forced the Koroheke family to endure a nearly month-long trial.

"You [had] every intention of doing what you did," the father said.

"You had no intentions of handing yourself in until you had no other options ... You could have stayed and faced the police but you ran like the victim."

Jason Koroheke said he didn't bury his daughter, as is Māori custom, but cremated her because Tai was still on the run at the time of her funeral and he feared him visiting her grave.

"I didn't want to leave her unprotected from you," he said.

"I failed the first time and I was not going to let it happen twice.

"You beat her courage out of her – she was so scared she didn't have the courage to ask for help."

Koroheke had spoken to her mother Nadine Koroheke about the abuse, while her father had also confronted Tai over his violence towards his daughter.

She also confided in friends but felt she could do nothing.

Jason Koroheke now cares for his daughter's children after a custody battle with their biological father.

"Those kids are my life – nothing matters to me but them," he said.

One of Koroheke's children asked her grandfather when she could talk to her mum, he explained.

"I said, 'when she dreams'. She said, 'I want to hurry up and go to sleep so I can talk to mummy'.

"I don't know what to say about their mother."

Jason Koroheke said his son, Nacyn Koroheke, and his partner, Samantha Douglas, were also victims of Tai's actions.

"You shot her in front of our son and his girlfriend," he said.

"You didn't even care what impact that would have on them.

"My son and Sam watched them die.

"They became victims because you made them victims when you pulled the trigger in front of them."

A statement from Nacyn Koroheke was also read by Crown prosecutor Mark Williams.

He said "it would help if I could forgive [Tai]" but he couldn't.

"You've brought shame on the name Tai," Jason Koroheke said.

"Your whanau are from the area of my whānau and now they have a murderer among them," he added, while not blaming any of Tai's family.

Justice Muir said Jason Koroheke's statement was among the "most moving such statements I have heard as a judge" and will "remain with me for many years".

"I hope that Mr Tai also listened careful to the human toll that his actions continue to extract," he told the murderer.

Through his lawyer, Peter Kaye, Tai argued for the jury to find him guilty of the lesser charge of manslaughter.

He said he showed no murderous intent and claimed the gun had discharged accidentally.

Tai, who has a long history of violent offending, maintains his position that it was an accidental death, the court heard today.

However, Kaye said his client told him this morning that he now recognises his crimes.

But, Kaye told Justice Muir: "That doesn't count for very much."

Koroheke "came into this world perfect but left broken and battered", the court heard from her sister.