Pamela Kulukula Purdie lamented the fact the "accusations" had derailed her coaching career.

A female sports coach who indecently assaulted a 12-year-boy while another child lay sleeping next to her has been sentenced to nine months' home detention.

Pamela Kulukulu Purdie, 24, appeared in the Rotorua District Court on Thursday after earlier being found guilty at trial of indecently assaulting and performing an indecent act on a 12-year-old boy.

The solo mother of one was found not guilty of a third charge of exposing seven boys under 16 years of age to indecent material.

In sentencing her, Judge Philip Cooper outlined how the assault occurred on the night of April 7 last year. Purdie, in her role as a school basketball coach, had invited team members to her home for a "team-bonding exercise".

"That plan changed and during the course of the evening, they ended up staying the night," Cooper said.

He said two boys slept in Purdie's absent flatmate's bed before she inserted herself between them.

"When the other one fell asleep, you indecently assaulted him."

Cooper said Purdie touched the boy's genitals and placed his hands on her breasts.

Referring to the trial judge's notes, Cooper said the boys involved were "clear and credible witnesses".

He also referred to a victim impact report on the indecently assaulted boy, which revealed the assault had had "a significant impact on the complainant and his family".

"He has really shut down and is exhibiting a loss of trust, in adults in particular."

Purdie was also granted permission to address the court herself, saying she wanted to "talk briefly about my achievements".

She listed a number of sport-coaching roles she had undertaken, and plans for further study "before these accusations".

"The impact of the accusations and guilty verdict have been devastating and affected my father's health," she said.

"I no longer coach."

At one point while reading her statement, Purdie wept. She also thanked her family and friends present in court for their support.

Passing down the sentence of nine months' home detention, Cooper described the ruling as "a finely balanced decision".

"You could easily be going to jail."

He said the starting point was between 18 months to two years in prison and noted there could be no credit for a guilty plea.

Cooper listed a number of aggravating factors around the offending, including Purdie's denial of guilt, the breach of trust given her coaching role, the disparity between her age and the victim's age and "the nature of the touching".

He also rejected calls from her counsel to exclude Purdie from the sex-offender register, citing her refusal to accept responsibility for the assault.

"It is concerning that you still maintain your innocence. That increases risk," Cooper said.

"In particular, you are in denial of what you have done and I think there is a risk."

Cooper also spelt out a number of home-detention conditions, including psychological assessment, to be followed by any counselling or treatment recommended, no association with the victim and no association with anyone under 16 without a court-approved adult present.