A man "gyrated" on a stranger before touching her breast and offering himself up as a "toy boy" - making him eligible for an open-ended jail term due to his history of indecencies.

But Damon Nicholas Rowe has avoided the prison sentence of preventive detention as a court worked to balance public safety with the 45-year-old's mental health needs.

On Friday, Rowe, who has paranoid schizophrenia complicated by substance abuse, was in the High Court at New Plymouth for sentencing on charges of doing an indecent act and indecent assault.

The charges arose from the afternoon of July 10 last year when Rowe approached a woman outside the Westown Shops in New Plymouth.

He engaged with her as if they knew one another, giving her a hug and then asking how she was.

But the interaction took a sinister turn when Rowe asked the woman if she wanted a "toy boy" and began "gyrating" his crotch while inching closer to her.

She pushed Rowe away and, as she did, he reached out and grabbed her breast and bottom.

As she continued to back away from him, he kissed her on the cheek before she left and alerted police.

Shortly after, Rowe sat outside the Subway store at the Westown Shops with his penis fully exposed.

It was reported to police that Rowe had been touching his penis for around five minutes as members of the public moved about the shopping strip.

Witnesses of the indecency included two teenage girls who reported the behaviour to a parent.

Rowe was arrested shortly after and has remained in prison custody since.

Damon Rowe was sentenced in the High Court at New Plymouth on Friday. Photo / Tara Shaskey

In court, Justice Rebecca Ellis explained that at the time of the offending the indecent assault charge was, for Rowe, a stage three offence under the three strikes regime.

That meant there was a possibility he could have served the charge's maximum penalty of seven years imprisonment without parole.

But last week the Government repealed the three-strikes law and so Rowe could now be sentenced without that being a factor.

However Rowe was still eligible for preventive detention, where prisoners may be released on parole but remain managed by Corrections for the rest of their life and can be recalled to prison at any time, and Crown prosecutor Cherie Clarke pursued the sentence.

She said the focus was not on punishing Rowe but on protecting the community, pointing out he is assessed as a high risk of reoffending.

Defence lawyer Patrick Mooney said prison would not address the needs of Rowe and therefore would not have any flow-on benefit for the public.

"Dealing with his problems provides a measure of protection for the community."

But Justice Ellis said the problem was determining an outcome that would best assist Rowe.

"The real challenge is coming up with something that is actually going to help Mr Rowe and, I suspect, the options don't seem to be very many."

She said a psychiatric report stated prison would have a "very considerable and negative impact on [Rowe's] already precarious mental health".

He has 70 previous convictions, 12 of which were for indecent behaviour, assaults or exposure.

Rowe has served a couple of short-term prison sentences which meant he has not been eligible for any rehabilitative programmes while in custody.

He also has a history of more than 50 psychiatric admissions.

A forensic mental health nurse told the court a mental health team had followed up with Rowe during his recent remand in custody.

During that time he had been compliant with his medication, she said.

Despite Rowe being eligible for preventive detention and reports stating he would likely commit another offence upon release, Justice Ellis did not impose preventive detention.

She said the offending was relatively low level and it was suggested any future offending was unlikely to increase in seriousness.

Therefore, a sentence of preventive detention would be unjustifiably punitive, she said.

Justice Ellis sentenced Rowe to 24 months imprisonment with release conditions.

But he would be immediately released due to his time served while in custody.

The release conditions included Rowe must reside with family in Whakatāne, he must consent to take his prescribed medication, that he submit to electronic monitoring, and he can not use drugs or alcohol.

He was visibly relieved to hear he would be leaving prison and repeatedly apologised for his offending.

"I was off my face, miss, I had no control."

- Tara Shaskey - Open Justice, NZ Herald