Prisoner Paka Leota who nearly killed another inmate fails in appeal against preventive detention

Paka Leota nearly killed a fellow inmate at Hawke's Bay Regional Prison in 2015. Photo / File

A man who attacked and nearly killed a fellow prisoner has failed in his appeal against a sentence of preventive detention.

Paka Leota attacked Jason Poi at Hawke's Bay Regional Prison in March 2015, leaving him with a such a severe brain injury he remained unable to walk or talk.

Justices French, Ellis and Woolford noted in the decision Leota posed "a significant and ongoing risk to the safety of the public", pointing to his "extensive history of violence".

"As the judge noted [at sentencing], it is difficult to conceive of a worse example of an assault in terms of its ferocity, and the severity of the effects on the victim who barely escaped death."

He was sentenced to preventive detention with a minimum period of eight years eight months imprisonment by Justice Karen Clark in September last year.

Leota assaulted Poi, with the help of another inmate, after blaming him for the failure of a plan to smuggle drugs into the prison.

He sought a definitive sentence of 11 years, which the judge assessed as appropriate before considering preventive detention. Under the three strikes law, Leota would not be eligible for parole as he was convicted of two earlier violent offences.

At the time of Poi's assault, Leota was already serving nine years for assault with intent to cause grievous bodily harm and wounding with intent to injure - the victim, like Poi, nearly died.

Leota appealed on the grounds that Justice Clark had not given enough consideration to two health assessors' reports, or considered the possibility of an extended supervision order (ESO).

The judges said an ESO would be inappropriate for someone as violent as Leota.

"ESOs were originally designed to better manage the risks of child sex offenders who are perceived as often ingratiating themselves to the victim through a process of grooming.

"An ESO is unlikely to mitigate the risk of someone like Mr Leota committing intermittent acts of relatively spontaneous and serious violence. "

The judges also noted in the decision that preventive detention had already been considered in 2013 during sentencing for the earlier assault.

"It may have been finely balanced in 2013 when Mr Leota was first considered for preventive detention, but it is not finely balanced now.

"The Judge was entitled to conclude that Mr Leota posed a significant and ongoing risk to the safety of the public."