Key Points:

Police today warned the public not to approach an escaped prison inmate with a long history of violence.

Arai Hema, 30, classified as a low security risk, slipped away from a work party outside the perimeter fence of Auckland Prison at Paremoremo yesterday afternoon.

He was tracked to a nearby road by a police dog but the trail disappeared and police believe he may have got into a vehicle, possibly driven by an accomplice.

Detective Inspector Steve Wood, Waitemata police district crime manager, said today his escape was "unusual and of concern" because after a decade behind bars he was due to be considered for parole.

"He has chosen to escape at a time when he is under consideration to achieve parole in the near future.

"The decision by any long-term inmate to escape from custody and thereby jeopardise the prospect of achieving parole is a rare occurrence. This inmate's behaviour indicates a degree of instability.

"We are not saying he is absolutely dangerous but there is potential danger there. We are concerned about his behaviour.

"We don't know what his state of mind is and therefore we are warning the public to stay well away from him and report him to police straight away.

"It seems totally bizarre he has done this."

Hema was jailed for 12 years after a 1998 sex attack on a 17-year-old girl at her home.

He tried to stab her but she screamed, and Hema attacked the girl's 78-year-old neighbour as he came to her rescue.

In 2004 he attacked guards at Hawke's Bay Regional Prison, throwing boiling water over one and hitting another in the head with a shovel.

That attack earned him another four years in jail.

Mr Wood said anyone who had seen Hema or seen any suspicious vehicle near Auckland prison yesterday should call police urgently.

"Do not approach him."

He also urged Hema to contact police to discuss handing himself in.

"The longer he is at large the worse this will affect his eventual release date," he said.