A sex attack victim has revealed he is unable to continue with normal life after being assaulted by an HIV positive man he considered part of his family.

Timi Tepo Robert James Hohepa, 49, was sentenced at Rotorua District Court on Tuesday to four years and six months imprisonment on one charge of sexual violation by unlawful sexual connection.

In an emotional victim impact statement read by the victim's mother, who like her son cannot be named for legal reasons, the 18-year-old victim said he considered Hohepa "as family".

According to the police summary of facts, Hohepa had become "an integral part of their day to day lives".

The summary revealed that in February 2016, Hohepa was at a house as part of a larger group which had a barbecue and drinks.

At around 11pm, just Hohepa and the victim remained in the garage.

"At around 4.45am the complainant woke to find the defendant committing an indecent act on him.

"The complainant pushed the defendant off and when he did so he saw the defendant's face."

Hohepa's lawyer Max Simpkins conceded the offending had impacted on the victim, but said his HIV levels meant there was a low risk of the victim being infected.

Crown lawyer Amanda Gordon described Hohepa's behaviour as having an aspect of grooming to it.

"Whether the risk [of HIV infection] was low or not, he [the victim] has had to take five weeks of anti-viral medicine."

Gordon also revealed Hohepa had been imprisoned previously for an indecent assault in 2008.

Sentencing Hohepa, Judge Tony Snell said that as the victim was asleep when the attack commenced "no issues of consent can arise".

"You are to blame, nobody else but you," he said.

He also referred to Hohepa's HIV status, the predatory nature of the offence and said the victim felt "utter devastation".

"You knew there was a risk when you commenced your actions," he said.

"Your whanau and others in the court know exactly what you have done."

The victim said that since the assault he had had to move home and feels "betrayed, hurt and lost".

"I can't trust the world around me. I can't carry on with normal life," he said.

"This is a life sentence for me and it should be for you too… use this sentence to get well and fight whatever demons in you that cause these depraved thoughts."

While the victim's blood tests have been negative for HIV, he will continue taking anti-viral medication for the next few months and testing will be ongoing, the court heard.

- Stuff