A West Coast woman has been jailed for three years for sexually abusing a 12-year-old boy.

Caroline Anne McClenaghan, 33, was found guilty of eight charges of unlawful sexual connection with a young person and three of doing an indecent act on a young person after a judge-alone trial in the Greymouth District Court in July.

Some of the charges were representative and had occurred on a number of occasions between February 2012 and September 2013.

At her sentencing in the Greymouth District Court on Friday, defence lawyer Richard Bodle said he was not shifting any blame onto the victim. However, he asked the judge to consider home detention because the accused was a woman.

"Males are different to females in relation to size and strength. Offending by males against females can involve invasive acts by an authority figure. The victim was larger and taller than the offender at the time," he said.

"The victim initiated contact. That doesn't make him culpable but it means there was no element of grooming. He did boast about it to his friends . . . skiting about what happened," he said.

Bodle said the victim had not made a complaint to police about the inappropriate behaviour. His grandfather had made the first complaint.

​Judge Stephen O'Driscoll said McClenaghan denied the offending and intended to appeal her conviction.

He said the court had heard from a number of witnesses with concerns about an inappropriate relationship between her and the victim.

"It's clear from the evidence I heard you have quickly developed a close relationship with the victim. You engaged in sexual activities with him on numerous occasions," he said.

The victim is now aged 18. His victim impact statement said he had a fear of new people as a result of what happened.

"I have no doubt, after seeing him give evidence, he was physically mature at the time but also that he was a vulnerable, insecure, emotionally immature boy. It's clear your relationship has had a significant detrimental effect on him," O'Driscoll said.

He said the offending was a gross breach of trust.

"You were the adult and he was a child. He bears no responsibility at all for this offending . . . Your counsel submits gender cannot be overlooked. Violent, overbearing and invasive acts by males against females are not present in this case.

"However, the absence of aggravating factors is not a mitigating factor. The law is designed to protect young people of either gender, from being abused," he said.

He started with a prison sentence of four years, but reduced it by one year because McClenaghan did not have any previous convictions.

He declined an application for permanent name suppression.