An altercation between family members on both sides of a murder trial saw a jury having to be taken out of a Whangārei courtroom while security guards had to step in between the two sides.

One of two brothers used a large knife to fatally stab a man the pair had earlier been fighting in the central city, a High Court murder trial in Whangārei has heard.

The brothers, from Whangārei, cannot be named due to legal reasons until at least the end of their trial, which started in front of Justice Timothy Brewer and an eight-woman, four-man jury on Monday.

The accused, aged 21 and 17 at the time of the incident, have pleaded not guilty to murdering 23-year-old Haze Peihopa during a violent clash on Bank Street at midnight on June 12, 2021.

The older brother has also pleaded not guilty to a charge of assault with intent to injure using a knife after he repeatedly swung it at another man during the large street fight where Peihopa was killed.

The younger brother pleaded guilty at the start of the trial on Monday to a charge of injuring Peihopa with intent to injure after he kicked him in the head while he was on the floor after being stabbed.

However, as CCTV evidence was played to the jury, including evidence of Peihopa being stabbed and collapsing on Bank St, in the central city, family members of the deceased approached the defendants, one yelling, “you should have f***ing killed yourself”, Radio NZ reported.

The judge, defendants, jury, and some members of the public were hurried out of the courtroom, amid shouting, wailing, and threats in the public gallery.

Court security intervened to break up the aggression before the jury returned a short time later.

Earlier, when opening the Crown case on Monday prosecutor Mike Smith said much of the evidence against the brothers involved CCTV and other video footage from the night in question, including from council cameras and from businesses in the area and people who had recorded parts of the brawl that had erupted between the two groups of people Peihopa and the accused were with that night.

Smith said the tragedy unfolded on Bank St between the establishments of Baccio and Roost, with a fight erupting literally in the middle of the road, with fighting going on around vehicles that had been stopped at the traffic lights.

He said on the night of June 12, 2021, the brothers had gone into town with some friends and around 11.30pm the group got into a confrontation with Peihopa, and some of his friends.

At some stage during this initial confrontation Peihopa hit somebody with a bottle, which did not break.

Smith said that the violent confrontation ended and Peihopa walked away back towards the bar with his friend while the brothers and their friends went another way.

However, Smith said, one of the brothers can be heard on audio from the night asking somebody for a “blade”.

”It’s difficult to hear, but police can hear (on the audio) him requesting a blade and then says words to the effect that he’s going to shank somebody.”

He said an associate then gives the large knife to the older brother who then heads towards Peihopa and his friend.

Smith said the older brother confronted Peihopa and swung at him a number of times, with the knife going into Peihopa’s chest, fracturing a rib, puncturing a lung and severing his pulmonary artery – which provides blood to the lungs, then hitting his spine. Peihopa staggered away then collapsed into the road and fell into the gutter. It was then that the other brother kicked him in the head, “like kicking a football”, Smith said.

The older brother then waved the knife several times at Peihopa’s friend, which was what led to the assault with intent to injure charge against him.

He said the brothers then left the scene, walking down Vine St towards the carpark. The knife was discarded in Vine St and the brothers were arrested near the toilets in the Vine St Carpark. Despite the best efforts of first responders, Peihopa died.

Smith said the knife can be clearly seen in the hands of the older brother, glinting in the CCTV footage.

He said in order for the Crown to prove the charges against the brothers beyond reasonable doubt it had to convince the jury that there was intent from the brothers to either kill the man or that they stabbed him knowing that death or serious injury could occur from their actions – in effect they were reckless.

Smith said a pathologist’s report would confirm that it was the single stab wound to the chest that killed Peihopa. He said the evidence would show that the older brother fatally stabbed Peihopa and that the younger brother aided him by being involved in the altercation.

In his opening address on behalf of the older brother, defence lawyer Steven Lack said his client admitted delivering the stab wound that killed Peihopa.

”There’s no dispute about that,” Lack said.

What was in dispute was the intention at the time the blow was delivered, saying the jury cannot be sure his client intended to kill with the blow, nor that he intended to cause serious bodily harm knowing it was likely to cause Peihopa’s death.

He said both sides used weapons in the fight, but Lack said his client did not bring a knife but was given it after the initial altercation. Lack said his client was also intoxicated from alcohol and nitrous oxide, making it difficult to process the consequences of his action.

Ron Mansfield KC told the jury, his client was not involved in the causing of the fatal injury.

”He simply wasn’t involved with causing the fatal injury.”

Mansfield said the teenager, who was just 17 at the time of the incident, was hanging with his older brother when they became involved in the street fight. It was a fast and chaotic incident without coordination, Mansfield said.

After Peihopa was stabbed, the teenager “stupidly” kicked him, which reflected the fact he had no idea he was fatally stabbed and lying in such a bad state, he said.

The trial is expected to last two weeks.

■ Additional reporting, Sam Olley, RNZ