Hastings man Trent Owen Ngaruhe Hapuku has been sentenced to nine years in prison for killing his partner's five-month old son, who interrupted him while playing a video game.
Hapuku delivered the fatal blow to Mikara Reti while alone with the infant in his girlfriend's Flaxmere sleepout on January 11 last year.
The 23-year-old appeared for sentencing in the High Court at Napier this morning after being found guilty of manslaughter last month.
Justice Forrest Miller imposed no minimum term of imprisonment, but said there was an "available inference" Hapuku had lost his temper with the infant while he was concentrating on a PlayStation game.
Mikara's mother Jamie wept while reading a victim impact statement and described her son as "the best baby anyone could ask for".
"No parent should have to bury their child ... I'll never forgive myself for it," Ms Reti said.
Justice Miller said Hapuku struck out once in a moment of anger, irritated that the baby had interrupted his focus on a Playstation game.
He said the court saw similar situations far too often in which a young man failed to bond with his partner's children and the home became a dangerous place, Newstalk ZB reported.
Hapuku was found guilty after a jury deliberated for three and a half hours following a trial early last month.
Hapuku had denied doing anything to cause the death of baby Mikara, who was pronounced deceased soon after arriving with Hapuku and mother Jamie Reti at Hawkes Bay Hospital in Hastings on the night of January 11 last year.
The Crown produced no evidence of any actual assault by Hapuku, but contended only he could have been responsible for the "blunt force trauma" which it said led to the splitting of the child's liver and severe internal bleeding which caused the death.
Hapuku had been in charge of the infant in a sleepout at Ms Reti's parents' Flaxmere home for much of the previous hour to 90 minutes, while Ms Reti was inside the house feeding and bathing her elder son.
Evidence was given that for much of the time, Hapuku had been focused on playing a PlayStation game.
Calling expert evidence to counter the claims, the defence contended the injury could have been inflicted earlier and argued the Crown had not excluded all other possibilities.