The man who was stabbed by his son was a brutal and controlling bully, a High Court trial has heard.
The son, father and many of the witnesses in the case at the High Court in Auckland cannot be named, due to wide-ranging suppression orders.
The Crown says the son stabbed his father, knowing that his actions could cause death and he should be found guilty of murder.
The lawyers for the son say he was acting in self-defence.
In her closing address, defence lawyer Denise Wallwork said her client, his mother and siblings had all been victims of family violence and lived in constant fear of their father.
On one occasion when her client was just a boy his father picked him, his siblings and mother up from a Women's Refuge where they had sought shelter.
He drove them out of town to a paddock where he pulled his wife out of the car while the children looked on.
"The beating consists of punching her head, kicking her in the face, kicking her in the ribs - while she is already down on the ground. It was a severe beating."
Ms Wallwork said her client frequently stepped in to take a beating from his father, in order to save his mother.
On the night he was killed, the father had beaten his wife while their young baby was in the house.
"Punching her numerous times in the head and face, she falls down, she tries to put her arms up to protect herself - he just started booting her in the ribs."
She was eventually able to get out of the house and make the 30-minute walk to where her son and daughter lived, with her baby in a pram
But her husband, high on methamphetamine, followed.
On the third occasion, the family barricaded themselves in the house as their father went around kicking at the door, putting his hand through the windows and yelling threats.
When he eventually drove off in the daughter's car, they thought he had gone and the son armed himself with a knife and went to investigate.
But his father was actually on the deck.
Ms Wallwork said the son was subjected to a surprise attack in the dark and was overpowered by a violent and aggressive man.
"In those circumstances, you may think that stabbing five or six times was perfectly reasonable."
The son didn't flee the scene, instead he held his father, telling him how sorry he was.
She quoted from the son's police interview that was recorded just hours after the killing.
"I didn't mean to do it. I hope he doesn't die. He's a bastard but I love my dad."
Crown prosecutor Gareth Kayes said before the attack, the son knew the police were on their way and that his father had been locked out of the house.
The son stabbed his father six times with the knife, including a fatal blow to his chest that nicked his lungs and the sack holding the heart.
In contrast, the son had few injuries - a sore back, sore ribs and a sore face from where he was punched.
"Was he really in such jeopardy, in the circumstances as he believed them to be, that he needed to kill his father? I suggest to you the evidence is he was virtually unharmed - a few scrapes, bumps and bruises and what that highlights, in the Crown's submission to you, is that the defendant's actions that evening were excessive."
Mr Kayes quoted the son from his interview with the police.
"Near the end of his own interview, he says: 'Look, I don't feel I handled it the right way'. And the Crown says no truer words have been spoken. Later in his interview he said: 'I'm not trying to justify what I did, I know it wasn't right'."
Mr Kayes acknowledged the father had been nasty and hostile on the night.
"But I suggest to you the worst the defendant believed he could receive was a lumping, an assault, a hiding."
He said the force that was used was simply not reasonable.
Tomorrow Justice Duffy will sum up the case before the jurors retire to consider their verdict.