The 55-year-old was jailed in April for at least six years after admitting to the manslaughter of Karen Ristevski at the couple's Avondale Heights home in June 2016.

The fact Ristevski could walk from jail on parole by December 2023 angered his wife's family as well as prosecutors who appealed the sentence on the grounds it was manifestly inadequate.

The killer refuses to say what he did to his wife of 27 years before bundling her into a car and hiding her body at Macedon Regional Park, where it was found eight months later.

Brendan Kissane QC, acting for the Office of Public Prosecutions, told the Court of Appeal the killer's "wheel of lies" about his wife's disappearance and refusal to say how he killed her warranted a harsher punishment.

"I accept that he has a right to silence that he maintains up until now," Mr Kissane said on Friday.

But he added the killer's dumping of the body and continued silence "indicates that something bad happened in the house."

"He hasn't put forward anything to positively say that this was just above an accident, for example," Mr Kissane said.

He said the victim's family were left to deal with the added grief of not knowing what happened, with the jail sentence failing to adequately reflect the crime's affect on them.

Ristevski played a mournful pallbearer at his wife's funeral and only admitted to manslaughter on the eve of his trial, after the Supreme Court ruled there wasn't enough evidence to secure a murder conviction.

He was jailed for a maximum of nine years, with Justice Christopher Beale saying he did not have enough information to determine the severity of the killing.

The maximum sentence for manslaughter is 20 years but with a six-year non-parole period and 491 days' pre-sentence detention, Ristevski could be out in four years.

"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," the judge said at the time.

But Victoria's Director of Public Prosecutions says Justice Beale made a mistake.

"(The judge) mischaracterised the seriousness of the offence because there was no evidence as to how Karen was killed," the DPP said in a submission to the court, released just before Friday's hearing began.

Ristevski's lawyer, David Hallowes SC, told the court Justice Beale couldn't have handed down a sentence based on what he didn't know.

"The judge can't determine the nature and the duration of the violence," Mr Hallowes said.

"You just don't know the circumstances."

But Chief Justice Anne Ferguson pointed out this was only because "the one person who knows remains silent".

Mr Hallowes also argued Ristevski had positive character references, no prior convictions and prosects of rehabilitation in his favour.

The Court of Appeal has reserved its decision.

Australian Associated Press