A Hutt Valley man who felled a father of three with a single punch, killing him, has been forgiven by the victim's family.

Felipo Sipaia died in Wellington hospital on August 14 last year after he was punched in the head by Jonathan Ioata during a confrontation between two groups in Lower Hutt.

Sipaia fell to the ground, hitting his head, and never regained consciousness. Ioata, 22, was found guilty of Sipaia's manslaughter by doing an unlawful act.

He was jailed for four years and nine months by Justice David Collins in the High Court at Wellington.

Tears ran down Sipaia's wife Fei's face as she read out her and her mother in law Nuuao's victim impact statements to the court.

She said Felipo had been a good husband and an even better father.

"I am always cheerful. When I see people I smile but deep down I'm hurting. I have lost my best friend, my husband and the father to my children. When I look at them my heart breaks."

Fei Sipaia told Ioata she did not have hate for him, but she wished he had not done what he did.

"I forgive you for your actions that night, I hope you can forgive yourself.''

Her mother in law said she cried herself to sleep and woke up crying.

She had lost interest in anything including her work and food.

She said she believed in God's will and she forgave Ioata and wished him well.

Justice Collins said he was deeply impressed by the words of both women calling them remarkable for their forgiveness.

He said Sipaia had not seen Ioata's punch coming and could not defend himself.

"Your punch was deliberate, powerful and probably knocked him out.  He fell and hit his head."

Justice Collins said either the punch, hitting his head or a combination was what killed Sipaia.

He said it was unnecessary and gratuitous and intended to cause serious harm.

He called Ioata sadly typical of young men in New Zealand, with a poor upbringing, limited education, alcohol issues and with a testosterone fuelled belief they were bulletproof.

Ioata's lawyer Kevin Preston said it was not premeditated, there had been no plan to have a fight but there was a tragic instant after senseless goading and text messaging and was completely avoidable.

He said Ioata had had no appreciation of the consequences of a single blow before this.

- © Fairfax NZ News