Onitolosi Etuini Atiai Latu, 31, was found guilty by a NSW Supreme Court jury in December of murdering his girlfriend Rhonda Baker in Liverpool in August 2016.

"It was yet another violent beating, inflicted as part of a sickeningly repeated pattern of physical subjugation of Ms Baker in the context of her telling him to leave or that she would leave him," Justice Julia Lonergan said in Sydney on Friday.

"On this occasion, however, it was to a new level of viciousness."

Family and friends had tried to help Ms Baker escape the "dire situation" with Latu as far back as 2010.

She'd been subjected to numerous physical attacks and psychological control, the judge said.

Justice Lonergan on Friday jailed Latu for 28 years with a non-parole period of 21 years as Ms Baker's family wept in the public gallery.

The 26-year-old suffered facial and rib fractures, a "caved in" eye bone and one-centimetre deep cuts on her lips.

Ms Baker died in hospital from a brain injury as a result of the multiple blows Latu inflicted to her head.

"She's the nicest girl ever and we all miss her so much," her father, Tim Tetava, told reporters outside court.

In his victim impact statement, Mr Tetava had urged the judge to jail Latu for a long time.

"It is hard for me to accept that Rhonda is gone forever while he is still alive," he wrote.

Justice Lonergan said Ms Baker must have felt a "terrifying powerlessness" against her much larger boyfriend before the "murder of extreme brutality".

"There is no doubt that night, for whatever reason, he acted as he often did, resorting to his fists to show his displeasure," she said.

Latu had a tendency to use physical force on the "head region" of female intimate partners when he was angry - pulling their hair, knocking them unconscious or karate-kicking them in the face.

The jury saw emails exchanged between Ms Baker and Latu detailing her fear of his temper.

Ms Baker sent herself an email in April 2016 directed at her on-again, off-again boyfriend.

"You tell me every single day how s*** I am, how you can do better and you don't need me," she wrote.

"It just confirms for me again that I don't exist, I mean nothing to you ... and there's no future."

Work colleagues gave evidence Ms Baker would wear sunglasses and scarves to cover up her bruises. Some hatched plans to get her away from Latu.

One friend testified Ms Baker had said she couldn't leave Latu unless she knew he was going to jail for "a very long time" because otherwise "he would find her and hurt her".

Darcel Baker said her daughter became a victim of Latu's "utter contempt for women".

"A partner's role is to care and love but instead she suffered a life of constant abuse, harm and threatening behaviour," she said in her victim impact statement.

"She had no chance of ever surviving."

Latu stared blankly ahead as he was jailed on Friday. He had shown no remorse and continued to deflect blame, the judge said.

He'll be eligible for parole in August 2037 but was warned the government can apply for him to be held in detention or receive further supervision if he's determined to be a high-risk offender.

1800 RESPECT (1800 737 732)

Lifeline 13 11 14

Australian Associated Press