Anastasios Karatzas, 70, was found guilty of murdering his wife Georgia at their Mount Waverley home in 2017.

"I love my father more than ever and I have forgiven him for what he has done," Dimitra Karatzas told the Supreme Court on Wednesday.

Karatzas wiped away tears as his daughter delivered the emotional statement.

"Mum was my rock and will forever be with me. I miss her but she is forever in my heart," Ms Karatzas said.

"One tragedy does not define who Anastasios 'Tom' Karatzas is to me and to so many other people."

His daughter said she asked herself what she could have done to help prevent her mother's death.

And while she had forgiven her father, she said what he did was beyond comprehension.

"I don't think I will ever come to terms with what happened," Ms Karatzas said.

Karatzas had been struggling with depression for years and "snapped" the day he killed his wife, lawyer Theo Alexander said at the pre-sentence hearing.

His wife was strangled with an electrical cord and was found facedown in her laundry.

Karatzas client was "deeply remorseful, affected and pained by what he did", the barrister said.

"It does seem absolutely clear, the least deserving person in his life really was ultimately the victim of this offence."

Justice Christopher Beale agreed Karatzas's mental illness was a relevant factor in the case.

"His mental illness explains in large measure why he snapped," the judge said.

Karatzas had been battling depression for more than a decade, the court was told.

Senior crown prosecutor Mark Rochford QC accepted Karatzas was remorseful but said it was the court's duty to uphold the sanctity of human life.

"The deceased was loved by her family. She was killed by the person who should have protected her from violence rather than subjecting it to her," Mr Rochford said.

Karatzas is due to be sentenced in September.

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Australian Associated Press