A father and daughter who had consensual sex could be heard in the act by other house occupants.

On at least one occasion, an occupant walked in on the pair having sex.

When police were alerted, the father – in his 70s – told officers he wasn’t doing anything wrong.

The Waikato woman, who was in her late teens at the time, appeared for sentencing in the Hamilton District Court on Monday on a charge of incest.

She applied for a discharge without conviction, and has continued interim name suppression pending a hearing in November.

Detailing the facts, Judge Tini Clark explained the woman had a “complex” background.

She had only recently met her father before offending, and soon after moved in with him.

The pair shared a bed, and the affair began.

Other house occupants regularly heard the pair having sex, and openly talking about having sex together.

On at least one occasion, an occupant walked in on the pair having sex.

When questioned, the father denied any wrongdoing, while the daughter declined to make a statement to police.

Reports prepared for sentencing showed the daughter had post-traumatic stress disorder, ADHD, fetal alcohol spectrum disorder [FASD], and a “mild or moderate intellectual disability”.

Crown prosecutor Lexie Glaser opposed the woman’s application. She said she had breached the court’s non-association order with her father multiple times.

That could see the woman put herself in another risky situation in the future, Glaser said.

It only stopped when her father was put in custody.

However, the woman’s counsel, Alvina Tu’inukuafe, took issue with that example and said it was her father who contacted her, and she called police on him.

“So there has been a change in her attitude,” she said.

In assessing the application, Judge Clark said it was clear the woman “has a number of different issues and that is important from my perspective because it means that although she is an adult, her level of functioning is not age appropriate”.

“It is below that.”

While the judge accepted the woman’s behaviour was “utterly unacceptable”, she deemed her “highly vulnerable”.

That placed higher culpability on her father, “who is a man of more mature years”.

“Someone who would have understood her background ... and someone who had a higher obligation in my view at least to avoid exactly the situation that has arisen here.”

She said it was hard to determine whether manipulation was involved, but the reality was the woman was “fully involved with what occurred and seemed to pursue ongoing contact even when forbidden to do so through bail conditions”.

After deeming the gravity of the offending at a moderate level, she adjusted that to low, given the woman’s vulnerabilities.

A conviction could hinder the woman’s future employment, she said.

“There is no way that this conviction will not give rise to queries and further discussion in relation to a prospective employer.

“I don’t think it will be helpful for [woman] to have to explain what occurred in order to get herself a job.

“I think that will be harmful to her progress going forward, but I think it’s important to mention that because in my view, people will be curious, and will want to know, so I think it is highly probable that [woman] will have to revisit events with respect to employers and so on, simply due to the nature of the conviction.”

She agreed to grant the application.

“It is not a signal that this is not offending which should not be denounced or deterred; it absolutely is.

“But instead I’m taking into account [woman’s] personal circumstances.”

The judge accepted the Crown was, and likely remained, concerned that the woman might not follow through on her promise to seek counselling and rehabilitation, but she hoped she did.

“Hopefully it allows her to put this matter behind her.”