Key Points:

In the middle of a violent rage Lange Fonoti told his pregnant girlfriend, "I don't want you to have this baby, I want you to have a miscarriage," before repeatedly punching her in the stomach, a court has heard.

Two weeks later, 17-year-old Palu Aholelei lost her baby.

Fonoti is now before the High Court at Auckland where he is on trial for procuring an abortion.

He has admitted one count of injuring his girlfriend but says he was not responsible for her miscarriage.

Opening the Crown's case yesterday, lawyer Kirsten Lummis told the jury the case revolved around a dispute between the couple on September 11 last year.

During that dispute Fonoti, 22, became so enraged that he gave his partner "a hiding" that allegedly led to her losing their baby.

"He wanted the complainant to have a miscarriage. He didn't want her to have the baby and he followed that up with hard blows to the stomach."

Ms Lummis said on the Friday before the attack the couple had heard their 15-week-old fetus' heartbeat for the first time.

On the Sunday they visited Ms Aholelei's family but Fonoti became jealous at the lack of attention he was getting and they fought on the way home.

The next morning Ms Aholelei woke to hear Fonoti abusing her.

"This time about the fact he hadn't received a phone call from her uncle who was supposed to be setting up a job [for him]."

Ms Lummis said Ms Aholelei tried to calm Fonoti down but he became more enraged.

That rage escalated into a violent 30-minute attack which started with a closed-fist punch to the face.

It continued with a flurry of other punches to the body.

The Crown says Ms Aholelei tried to leave but was caught in the hallway and dragged back to the bedroom by her hair.

At one stage she was told to clean up blood in the hallway from her bleeding nose.

Back in the bedroom, Fonoti allegedly said something like "I don't want you to have this baby, I want you to have a miscarriage" before making Ms Aholelei lie on her back with her hands out to her side.

It is alleged he then delivered a number of hard punches to her stomach.

"When she tried to defend herself he got angry."

Ms Lummis said Fonoti made more comments about not wanting the baby before picking up a chair and swinging it over his head.

"It struck her a number of times in the stomach but she blocked some with her arms." While Fonoti tried to pull part of the bed apart to use as a weapon Ms Aholelei tried to escape again.

This time she got to the front door and, despite his attempts to pull her back, she ran to the neighbours'.

In hospital Ms Aholelei was treated for a number of injuries, mainly extreme bruising and a fractured nose.

Doctors did not carry out any tests on the fetus as they felt there was nothing that could be done if any damage had been inflicted.

Two weeks later Ms Aholelei, who was then 17 weeks pregnant, was admitted to Middlemore Hospital with a miscarriage.

In a brief opening statement from the defence, lawyer Carolyn Rameil told the jury there were "two sides to every story" and she asked them to "keep an open mind until the very end of the trial".

The trial continues today.