Online predator Cameron Stuart Hore has been jailed for four years and one month for offending that included posing as a young woman online to sexually exploit young victims.

Hore, 28, had admitted 12 charges before his sentencing in the High Court at Christchurch: two of blackmail, two of obtaining credit by deception, and eight of sexual exploitation or attempted sexual exploitation.

Hore is deaf and a sign language interpreter was in court for him.

The victims were found after police seized Hore's computer after a complaint and analysed just one month of the 9306 chat logs accumulated over 15 months from September 2009 to November 2010.

Nine of the 14 victims traced from that month were willing to talk to police.

Crown prosecutor Pip Currie said it had been premeditated and planned offending, using false identities to obtain personal details. The offending occurred on the internet and by text, and there was sexual offending on occasions when face-to-face contact occurred.

"There has been ongoing manipulation of boys and young men for his own sexual gratification," she told the court.

The victims had been aged from 11 to 19.

"This offending didn't surface because most of these young men were either unaware that there was anything sinister or untoward - they thought they were dealing with a young woman - and also because of their embarrassment about what had occurred."

Hore was assessed as being at moderate to high risk of reoffending.

Defence counsel Margaret Sewell said Hore accepted he was aware of the ages of the victims.

"He was in the grips of an increasing and escalating and out-of-control habit."

She said the offending had arisen from loneliness and isolation, and abuse as a child.

"It is clear he has been a victim, he's been isolated, and the adults in his life have let him down."

Justice Lang noted that Hore continued to offend against five victims after his arrest in January 2011, while he was on bail.

The offending involved 11 young victims.

If one of the victims had not gone to the police, it was unlikely that Hore's offending would have been uncovered, because of the victims' reluctance to admit what had happened, said the judge.

Justice Lang reduced the sentence because Hore had been profoundly deaf since birth, which resulted in his isolation through being unable to form relationships. He also reduced the sentence because of Hore's guilty pleas.

None of the victims were in court to see the sentencing.

- © Fairfax NZ News