It is irresponsible for local body politicians to ramp up public fear of sex offender Stewart Murray Wilson, a Victoria University professor says.
The Department of Corrections wants 65-year-old Wilson, dubbed "the Beast of Blenheim" for his sexual offending, rehoused in the Whanganui Prison grounds early next month.
Wanganui councillors Michael Laws and Ray Stevens held a public meeting about stopping the move, attended by about 200 angry and upset people.
"I think they have failed the public on this one, creating unnecessary panic and angst among people that isn't justified. What I would like to see is some sane, measured response," Professor Tony Ward said.
He is a clinical psychologist with expertise in sexual offenders and their rehabilitation. He hadn't met Mr Wilson, but said given his age he was unlikely to reoffend.
"The reoffending rate for very high risk people over 60 is about six per cent."
Most sex offenders stopped offending, with the help of their family and friends.
In the past Mr Wilson had planned his offending, and under the stringent parole conditions he has been set he was unlikely to have the opportunity.
"He has in the past had quite elaborate plans and plots. He just doesn't pounce on people."
Talk of castration and attacks with baseball bats was very unhelpful, Professor Ward said, and could lead opponents to commit criminal acts themselves. Instead, the best way to rehabilitate sex offenders was to keep them in the midst of other people - where they could be watched - and give them support.
"Some degree of social support and acceptance is essential.
"Social rejection and antagonism actually makes it much less likely that they can become socially responsible."
Wanganui councillor Ray Stevens' efforts to have Mr Wilson trespassed from business premises were extreme, Professor Ward said.
"I wonder if people have such an extreme response to men who beat up their wives."
It would be more helpful if local body politicians got informed of the real facts and then told the public.
Professor Ward said the overly punitive stance from Wanganui people also undermined the justice system. Mr Wilson had already been severely punished, and would still have grave restrictions on his liberty.
It was time for him to feel he had squared his debt to society and get on with other things.
"People won't allow him to do this. They want to keep punishing. It really undermines our justice system."
He described the fervour at Wanganui's public meetings as a type of "moral panic".
"People have periods of almost hysteria where they think that anyone of high risk is going to wreak havoc."
People who had been sexually abused could have particularly intense emotional responses, especially if they were still feeling raw about it, he said.