One of New Zealand's most violent murderers has his first outing before the Parole Board on Friday

Clayton Robert Weatherston was jailed for life in 2009, with 18 years minimum non-parole - for stabbing ex-girlfriend Sophie Elliott more than 200 times in 2008.

Elliott's mother, Lesley, was home and tried to help during the attack.

Her father, Gil Elliott, says he's told by the Parole Board Weatherston hasn't engaged in rehabilitation.

He says he maintains Weatherston's mental state will be unchanged from when he went to jail.