A woman will spend the rest of her life battling demons inflicted upon her by four young men, who all took part in raping her for hours.

Judge Lance Rowe said she was degraded, violated and treated as "less than human" and a "sexual plaything" by Lou William Harrison, Meha Hemi Taylor-Haeata, Renee Chaz Haeata and Anthony Simon Hirawani during the ordeal.

The quartet were all sentenced in the Palmerston North District Court on Friday to lengthy jail terms for their roles in the gang rape, which the judge simply described as "very serious sexual offending".

He said it was pointless trying to figure out who was the most serious offender as they acted as a group, encouraging each other during the victim's horrific October 2014 ordeal.

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The four had been drinking at a Palmerston North house for most of the day, despite Harrison and Haeata being 15 and 16 years old at the time, respectively.

The woman, then a teenage girl, was there and had consensual sexual contact with Hirawani, who was 23 at the time.

Taylor-Haeata, 20 at the time, went to the room and found the girl in there.

He called her a b.... and said she was "in my kingdom", before calling the others into the room.

A knife was put in the door to make it harder to open, and Hirawani put a chest of drawers across the door, before the rapes began.

She was raped multiple times, sometimes at the same time by multiple rapists, with one of the rapists saying afterwards the ordeal lasted at least two hours.

The judge said it was important to note she asked to go to the toilet multiple times to seek refuge.

"This refuge was denied every time, because she was accompanied by one of you every time."

She was subjected to multiple indecencies while in the toilet, including once while Harrison was in there with her.

Haeata tried to force his way into the toilet at that time, but Harrison told him to wait and as he would get "a turn" later, the judge said.

The girl was left bleeding, bruised and psychologically scarred. She suffers from post-traumatic stress and depressive disorders, tried to commit suicide afterwards, and has relocated in an attempt to feel safe.

Crown prosecutor Michael Blaschke​ said the victim had shown courage by coming forward despite the "horrific and incalculable harm" inflicted.

"The effects of this offending are going to stay with her for the rest of her life."

Psychological reports were prepared for each offender before sentencing, shedding light on their backgrounds.

Haeata was homeless, selling drugs and using synthetic drugs and methamphetamine by the time he was 15.

He initially denied the offending, but had since expressed shame at his actions and a desire to take part in rehabilitation.

Harrison had smoked marijuana since the age of 8, and started drinking alcohol when he was a child.

While he described the victim in vulgar terms to a probation officer and said he planned to serve his full term, a psychologist noted he was interested in rehabilitation.

Hirawani was the only defendant to plead guilty without having a sentence indication, which defence lawyer Steve Winter was due to him realising the harm he had caused.

Taylor-Haeata's psychological report was the most concerning of them all as he did not appear remorseful, the judge said.

He started abusing alcohol when he was a child, and was hospitalised for alcohol poisoning when 13.

He had also been seriously assaulted as a child and seen many instances of domestic violence towards women, which may have shaped his attitude towards women, the judge said.

The judge addressed the large family presence in court for the rapists.

They have been there at most court appearances, and many yelled out lines like "that is not how it even happened" when the rapists pleaded guilty.

The judge said their support would be the difference between the rapists leading offence-free lives or not.

Taylor-Haeata was given 11 years' jail, as he was also being sentenced for burglary, breach of sentences and the May 2017 aggravated robbery of Liquorland College St in Palmerston North.

He committed both those dishonesty offences while on bail for the rapes.

Haeata and Harrison were both given seven years' jail, while Hirawani was sentenced to seven years and two months' prison.