Justice Christopher Beale sentenced an emotionless Ristevski, 55, to a maximum nine years' jail with a six-year non-parole period for killing his wife Karen Ristevski, 47, in their Avondale Heights home in Melbourne's north-west on June 29, 2016.

With time served, Ristevski could be released by his 60th birthday.

In a statement to The Age, a spokesman for the Office of Public Prosecutions said the sentence was now being reviewed.

"This sentence, like all sentences, will be under review for possible appeal. However, no decision has been made as yet," he said.

Victorian opposition leader Michael O'Brien said the sentence showed Victoria had a "legal system, not a justice system."

"Too many Victorians will be looking at the sentence handed down to Ristevski and shaking their heads," Mr O'Brien said.

"That's not justice, that's not justice or anything like it, but that's where we are in Victoria at the moment."

Outside of the Supreme Court in Melbourne following the 45-minute sentencing on Thursday morning, Karen's brother Stephen Williams spoke of his frustration.

"Nothing was going to bring Karen back, but today was about justice," he said.

"We didn't get justice today, at all."

One of the critical reasons for Justice Beale's sentence was he could not determine whether the offence was in the mid or upper range of manslaughter.

Though manslaughter carries a maximum 20 years, latest figures from the Sentencing Advisory Council showed the average sentence ranged from a minimum seven years and three months in 2015-16 to nine years and two months in 2017-18.

The average length of non-parole periods in the last financial year was six years and two months.

Justice Beale said the Ristevski case was clearly not low-range manslaughter because of the aggravating domestic violence aspect.

"Without knowing the level and duration of the violence perpetrated by you, which caused your wife's death, I simply cannot say whether your offending was mid or upper range," he said.

Justice Beale said the fact Ristevski kept silent on how his wife died did not mean the court could assume that the killing was in the most serious category of manslaughter.

The judge took in account a number of other factors in the sentence. A major factor was the guilty plea to manslaughter, first offered in September last year, a month after Ristevski faced a committal hearing on a murder charge.

Justice Beale also found Ristevski's prospects for rehabilitation were good, citing his lack of criminal history and character references, which included a "striking" reference from his daughter Sarah.

Sarah described her father as "loving, caring, sympathetic, protective and charismatic".

"I have so many amazing memories with my dad that I will forever cherish, especially those memories of my parents together," she wrote.

"The love they had for each other and the marriage that they shared is something I hope to one day experience myself.

Justice Beale told Ristevski that after Karen, Sarah was his principal victim and her refusal to provide a victim impact statement and instead support her father was "out of love for you, no doubt."

"I mean no criticism of Sarah. Anyone with a modicum of compassion must understand that her predicament is an agonising one. Regrettably the sentence I must pass on you will add to her grief," he said.

Justice Beale said the most aggravating feature of Ristevski's act was his conduct after he killed Karen.

He dumped and hid her body in bushland at Macedon before he spun a web of lies to his daughter, the extended family, friends, police and the public.

Her remains were so decomposed an autopsy could not determine how she died.

"When Karen's body was eventually discovered after eight months, and she was finally given a proper funeral and burial, you acted as a pallbearer, playing the part of the innocent, grieving widower," Justice Beale said.

"The pretence - the rank deceit - only ended a few weeks ago when you pleaded guilty to manslaughter."

Justice Beale said Ristevski's refusal to say how or why Karen died in their Avondale Heights home has complicated, if not cruelled, the possibility of closure for her family.

In her victim impact statement, Karen's cousin Lisa Gray said "if Borce could do anything for Karen and her side of the family, it would be for him to take away the constant stream of images I experience almost daily, of Karen struggling for her last breath. The not knowing is worse than knowing."

Justice Beale said he could not find Ristevski was remorseful because of his continued silence.

Investigators believe Karen was killed in the bathroom of the Avondale Heights home. It was scrubbed "hospital grade" clean, they said.

They believe the couple argued about the financial plight of their clothing business, Bella Bleu, beforehand.

Ristevski was charged with murder in December 2017 after a lengthy police investigation, involving listening devices and analysis of CCTV footage.

In March, Justice Beale ruled that evidence about Ristevski's behaviour after Karen's death could not prove murderous intent in a ruling that ultimately led to the murder charge being withdrawn.

Ristevski, on the even of the murder trial, instead pleaded guilty to the lesser charge of manslaughter after months of repeatedly lying to his daughter, family members and the police about what he did that day and denying having any involvement.