Having tried for months to get his noisy neighbours thrown out of their house, Auckland man Dustin La Mont grabbed a knife and walked towards next door. Minutes later one man was dead and another was fighting for his life, prosecutors say.

La Mont, 25, is accused of murdering 24-year Nathan Matai Pukeroa outside a house in suburban Mount Albert in the early hours of December 3 and grievously wounding Mr Pukeroa's friend, Devaray-Junior Cole-Kurvaji, in the same attack.

Opening the prosecution case at the High Court at Auckland on Tuesday, lawyer Steve Hazard told the jury La Mont had spent months recording video of his neighbours, checking the licence plates of the cars visiting their home and complaining to police in a bid to get them thrown out.

Mr Hazard said the residents and visitors at No 21. Renton Road were "far from angels", with Mongrel Mob members frequenting the house, selling P there, committing crimes and frequently partying in the middle of the week with no regard for their neighbours.

La Mont had taken to social media to swear about his neighbours - who he lived next to for 18 months - and once even bemoaned the removal of the provocation defence for murder, he said.

"Never have I been more provoked to go on a murderous rampage," he quoted La Mont tweeting.

The night of the killing he sent out a long series of angry messages complaining about yet another party.

"Sounds like the mongrel s***f***s next door are having another midweek party. Yipee," one read.

La Mont then grabbed a blade and walked out onto the road in a rage, Mr Hazard said.

At about midnight, Mr Pukeroa and Mr Cole-Kurvaji followed La Mont out onto the road after seeing him peering down the driveway of No. 21 while passing.

Mr Pukeroa was visiting the house for a few days and Mr Cole-Kurvaji had only arrived for the first time six hours prior, Mr Hazard said.

In the confrontation that followed on the street, La Mont plunged the short blade into each man's neck in two quick strikes.

The knife went to the hilt into Mr Pukeroa's throat, killing him almost instantly at the scene, while the second strike went up to 10cm into Mr Cole- Kurvaji's neck, but had luckily missed his jugular, Mr Hazard said.

La Mont had then gone home, taken the knife apart and tried to get rid of the evidence, Hazard said.

"He took off his clothes, soaked them in bleach and shaved his beard off."

The defence will make its opening statement later in the day.

Mr Hazard said La Mont had told police he was defending himself from Mr Pukeroa and Mr Cole-Kurvaji.

But he could have "easily" escaped the situation without killing them, Mr Hazard said.

A jury of four women and eight men has been selected for the three-week trial.