The head of a union which represents prison officers says the sentence given to an inmate who killed a guard is derisory.
Latu Kepu, 22, pleaded guilty to the manslaughter of Jason Palmer after punching him in the head as he was being let out of his cell at Springhill Prison in North Waikato in May.
The 33-year-old prison officer fell to the ground and died in hospital the next day.
On Friday, Kepu was given six years and four months jail, with a non-parole period of just over four years.
Justice Heath said the sentence was to denounce the crime and deter others from assaulting prison officers.
Public Service Association national secretary Brenda Pilott says corrections officers believe the jail term is too short.
"I think most New Zealanders will be thinking that's a derisory sentence and will be sharing the disquiet and the distress of prison officers," she said.
The sentence will take effect once Kepu finishes his current jail term of two years and eight months for assaulting a police officer and a pregnant woman.