A man who killed a teenager who shot a water gun at him in Auckland's CBD has been jailed for seven years.

Photo: RNZ / Anneke Smith

Myron Robert Alf Felise, 31, appeared in the Auckland High Court for sentencing this morning after pleading guilty to manslaughter in November.

He attacked 18-year-old Eli Holtz as he sat strapped into a car at the intersection of Wellesley and Queen streets in the early hours of 27 January.

Mr Holtz, who was visiting from Whangārei, was being driven around the city by friends when he shot a water pellet at Felise, who was drinking with friends at Father Ted's bar.

Felise walked over to the car and punched the teenager in the face, smashed the water gun over his body and then knocked him unconscious.

He continued punching him until a friend pulled him away. Mr Holtz died in hospital the following day.

Family of both Mr Holtz and Felise packed the public gallery to standing capacity this morning before emotional victim impact statements were read aloud to the court.

Kirsten Holtz, who raised Mr Holtz for her sister, said her family was now broken and the impact of her son's death would span throughout their lifetimes.

She said she now regularly woke at 3am, 4am and 5am which she now realised were the times Mr Holtz was assaulted, resuscitated and the time of the morning two policemen knocked on the door of their Whangārei home to tell them she needed to get to Auckland quickly.

Felise sat in the dock, his eyes downcast, as Mr Holtz' sister Channelle Armstrong told the court his six punches had been such a small number, but with such heavy consequences.

She described her brother as a "gentle giant" who had been an amazing uncle to her children.

The court heard he was working at a local fish and chip shop and recently enrolled in NorthTec to pursue his dreams of becoming an actor.

Ms Armstrong told the court she had so badly wanted to see her brother graduate, marry and have children but said Felise had taken that away from her.

She said he had continued to take and take from her family, even as they mourned.

"In our culture it is custom to embrace the tūpāpaku, his body, but on day one we sat with him and we heard as his bones creaked and his body sank whenever somebody came to hongi my brother or kiss him. I remember running my hand over his forehead and feeling the cracks in his skull.

"His injuries from you Myron were such that we had to ask people to stop touching him as his body collapsed under the weight of our heavy hearts."

Mr Holtz's biological mother Lorr Ramage also spoke of the physical, mental and financial impact of her son's death.

"I'm so angry at you Myron ... you've stolen my only child."

Photo: RNZ / Anneke Smith

She said she missed his goofy laugh, gorgeous smile and generous heart and Mother's Day had been hard.

"I hid myself in my home. I didn't want to talk to anybody. I didn't want to see anybody. Am I even still a mother?"

She told Felise he had taken the one thing that mattered to her in "one act of stupid aggression".

"Myron Felise what you have done has destroyed my life and my family's life. Today you will be sentenced but soon you will be released and walking on the streets again. We on the other hand had been dealt a life sentence."

Felise leaned forward in the dock, bowing his head, when his own mother Soreta stepped forward and asked Mr Holtz for his family's forgiveness.

"I know my son made mistakes in life like all humans do and his actions this particular night ended up in a tragedy that was far from his intention. My prayers, Myron's prayers and ours, is that god will give you strength, peace and healing in your hearts to forgive him."

Justice van Bohemen described Felise's fatal attack as a gratutious act of violence but said it wasn't his first brush with the law.

Felise was 22 years old when he and five other men were charged with the murder of Manurewa liquor store owner Navtej Singh - shot dead in 2008.

He was found not guilty of murder or manslaughter but convicted of aggravated robbery.

The judge said it was clear Felise continued to misuse alcohol and use violence.

"Last time you did not learn from your experience. This time you better. But you will only learn if you own the problem and make it your mission to change your ways so you and others can be safe."

He jailed him for seven years with a minimum non-parole period of three years six months.

Whānau on both sides embraced one another outside the courtroom after sentencing.

Ms Armstrong said through all the grief an anti-violence campaign, called Justice for Eli, had given them hope.

"Through this campaign we have been reminded that people are good, people are kind and people care. My brother will continue to contribute good things to this world because that's exactly what he would be doing, were he still alive with us today."