The man who killed a Sky TV employee with one punch on Auckland's waterfront during the Rugby World Cup has been jailed for five years.

Kit John Murray was sentenced in the High Court at Auckland on Tuesday for the manslaughter of Billy Dawson, 34, who died on October 7 last year after an early morning fight near Spy Bar in Auckland's Viaduct Basin.

Murray was found guilty after a trial in August.

During sentencing, Justice Patrick Keane said that when Murray punched Mr Dawson he must have intended to do so with "as much force as you could muster" and that he would at least suffer a serious facial injury from the punch.

Mr Dawson, unable to stop himself from falling, hit his head on the concrete and started bleeding profusely from his nose and mouth.

While others went to assist him, Murray and his associates left the scene in a taxi, Justice Keane said.

Mr Dawson later died in hospital.

Justice Keane said that while Murray has expressed regret for what he did, he continues to maintain that he acted in self-defence and it was not an expression of remorse in its fullest kind.

Earlier, a victim impact statement of Mr Dawson's mother, Lee, read by Crown prosecutor Ben Smith, said the family didn't want to attend Murray's trial or sentencing because they wanted to "concentrate on how our son lived and not on how he died".

She said her son's death had caused her family to suffer "a grief that will never go away".

Amanda Kennedy, Mr Dawson's friend and flatmate, broke down as she told the court she had to deliver news of a friend's death for the first time in her life and she suffers anxiety attacks following Mr Dawson's death.