After yet another quarrel, Turiarangi Tai grabbed a shotgun and blasted his girlfriend at point-blank range - her nearby brother powerless to stop him - a Crown prosecutor has told an Auckland court.

Tai now stands trial in the Auckland High Court, after pleading not guilty to murdering 22-year-old mother-of-two Chozyn Koroheke, in April last year.

A woman is also standing trial alongside him, charged with being an accessory to murder for allegedly ordering Tai a taxi to evade capture by police.

The woman's name cannot be published by order of the court.

At the time of the shooting, Tai was sharing a three-bedroom home with Ms Koroheke and her brother and his girlfriend, prosecutor Mark Williams told the jury on Monday.

Tai and Ms Horoheke had been in a relationship only a short time.

"But it was one characterised by violence at (Tai's) hands," Mr Williams said.

In their last argument before the shooting on April 4, 2017, Tai had hit Ms Koroheke in the head with a rock, he said.

A month before that, he stabbed her, he said.

On the day of Ms Koroheke's death, the couple had been fighting again, with Ms Koroheke complaining to her brother that Tai had refused to talk to her all day.

He instead packed his belongings into his car. When he had finished, he called Ms Koroheke and asked her for a cigarette and petrol money.

"You haven't talked to me all day, why would I help you," she replied, according to Mr Williams.

The exchange appeared to enrage Tai, who shortly after burst into a small bedroom where Ms Koroheke and her brother and his girlfriend were.

Saying, "you f*** bitch", he bashed his girlfriend on the head with the barrel before lowering it and shooting her in the stomach.

Despite paramedics arriving at the scene just minutes later, Ms Koroheke died.

Tai managed to evade police capture for two weeks before finally handing himself in.

His trial is set down for just over three weeks.