A young woman who lost it when she found her ex-partner in bed with another woman was sentenced in the Hāwera District Court on Monday. (FIle Photo)

﻿A young Taranaki woman flew into a violent rage when she found her ex-partner in bed with another woman.

To make matters worse, Teneke Danielle Wineera's love rival was her own flesh and blood - her sister.

The Hāwera District Court heard that on January 3, Wineera went to pick up some belongings from the Eltham, South Taranaki home she used to share with her ex-boyfriend prior to their break-up three months beforehand.

The summary of facts said when Wineera arrived at the house about 9.55am, she found the pair in bed together.

Upon seeing this, Wineera pulled the blankets off the pair and then punched her sister in the head, before the ex-partner dragged the defendant away.

​READ MORE:

* Top police boss offers to intervene in sex assault case, as victims lose faith in force

* Pies stolen in Huntly robbery

* Environmental Court approves Waikeria Prison expansion

As the 20-year-old tussled with her former boyfriend, she punched him in the mouth with a closed fist, leaving him with minor injuries.

After being given permission to collect her personal items, Wineera confronted her sister again, punching her several more times. The two fought briefly before the male victim intervened.

Wineera's sister suffered a swollen lip, a black eye and cuts to her forehead as a result of the attack.

Judge Garry Barkle said the victim impact statements outlined how both complainants had not been surprised by Wineera's violent reaction. They have not had any contact with her in the weeks following the attack.

The judge said Wineera had shown no remorse towards the pair, as referred to in a recent discussion she had with a probation officer about the offending.

"You stated they were dead to you as far as you were concerned," he said.

Wineera previously pleaded guilty to charges of assault with intent to injure and common assault and at Monday's sentencing hearing lawyer Rajan Rai asked for supervision to be imposed.

He said Wineera, a first offender, lacked the ability to "deal with the situation she discovered."

"She was hurt, she was outraged and she was very distressed."

However, Judge Barkle believed there needed to be a punitive element to the sentence despite the circumstances of the case.

After taking into account her early guilty pleas and lack of previous convictions, he ordered Wineera to complete 100 hours of community work and a 12 month term of supervision.

A bid for permanent name suppression was made at the hearing by Rai but this was declined by the judge.