Senior Sergeant Mark Clayton said Sione Moala was sentenced in the High Court at Auckland on Tuesday after attacking a man outside a bar in April 2016.
Moala was given the two-and-a-half year sentence after being found guilty of wounding with intent to injure and fighting in a public place.
He would not be eligible for parole, Clayton said.
Clayton said Moala had approached a man he didn't know outside a central Auckland bar and in a "senseless and unprovoked attack", left him seriously injured.
