An Auckland man who has twice been convicted of stabbing to death his pregnant partner was ordered to serve a life sentence today with a minimum period of imprisonment of 15 years - slightly shorter than the minimum period he initially received six years ago.

Akash, 30, who goes by only one name, looked down at his lap through most of today's sentencing in the High Court at Auckland - wiping away one tear as Justice Mathew Downs described the more than 30 wounds he inflicted on 22-year-old Gurpreet Kaur in 2016.

"She was pregnant with your child," Justice Downs noted, adding that he agreed with the previous judge's contention that Akash's actions that day were barbaric. "Ms Kaur was entitled to look to you for protection."

Kaur was believed to be between seven and 10 weeks pregnant in April 2016 when she suffered about 30 cutting and stab wounds while inside Akash's car at a remote location in South Auckland. The attack, described as "frenzied and sustained" by the judge, included stab wounds to her abdomen and her head and a cut to the jugular vein on her neck.

Akash tried to cover up the murder, dumping her body down a ravine and disposing of his bloody clothes. But after a series of interviews with police days later, he eventually helped them find her body.

He pleaded guilty to murder months after the killing, stating in a letter to the judge then overseeing the case that he regretted his "wrongdoing and take full responsibility for my thoughtless actions".

"I feel utterly ashamed, guilty and disgust for what I've done," he wrote.

That judge ordered him to serve a minimum sentence of 17 years before he could be considered for parole.

But Akash later told mental health workers while in custody that he thought Kaur had been involved in a conspiracy to harm him. That contention became the basis of an appeal, and in 2020 his guilty plea was vacated so that a jury could decide whether he should be found not guilty by reason of insanity.

During his trial, which began in February this year and lasted nearly a month, defence lawyer Julie-Anne Kincade, QC, pointed to witness accounts and text messages that showed his behaviour had changed in the weeks leading up to the killing.

Crown prosecutor Gareth Kayes agreed that Akash was mentally ill at the time of the killing. But to be found not guilty by reason of insanity, it must be shown that he was so unwell he didn't know what he was doing was wrong. His attempt to hide the body and his multiple lies to police suggested he did know he had done something wrong, Kayes argued.

Justice Downs agreed.

"The jury rejected your insanity defence, and quickly," he explained, adding that the defendant had jealous tendencies and the relationship was volatile even before witnesses said he started acting strangely. "There was a mountain of evidence that you knew killing Ms Kaur was morally wrong."

Justice Mathew Downs, pictured in 2014, presided over today's re-sentencing of murder convict Akash. Photo / Sarah Ivey

However, he added, mental illness is still relevant when deciding the minimum period of imprisonment. Seventeen years would be manifestly unjust, he determined.

The judge also acknowledged the pain this year's trial had put Kaur's family through.

Gurcharan Singh, who testified through a Punjabi interpreter at the trial, stood silently before the judge as the sentencing hearing began. A police detective read aloud his emotional victim impact statement.

Listening to the testimony at trial was like having witnessed his daughter's murder firsthand, building on the trauma that began in 2016, he said.

"Gurpreet was the life of our house," he wrote. "She was the one who would laugh and bring happiness into my life. Gurpreet was very close to my heart."

She had been studying to become an early childhood education teacher and had promised her father that he wouldn't have to work anymore once she entered the workforce, he recalled.

But since her murder, Singh said he has become so mentally unwell that he has had to close down his labour supply and vegetable businesses. His wife is also unable to work, he said.

"I dream about Gurpreet at night. They are not pleasant dreams," he said. "I must take sleeping pills to get to sleep."

He fears he has cried so much it has affected his sight, he added.

"This man has killed my daughter and took her away from me with his despicable act," Singh told the judge as he concluded the letter. "He has taken our daughter from us and ruined our lives.

"He has taken all the happiness from our lives."

Akash didn't look up or make eye contact as the father left the area in front of the judge's bench and returned to the gallery in the back of the courtroom, to sit by his wife's side.

The murder convict did, however, wipe tears away about 30 minutes later as he was ordered to leave the courtroom to begin serving his revised sentence.