In sentencing Bednar, Justice Andrew Tinney found he had planned the "ferocious" attack against his mother after blaming her for a series of involuntary mental health admissions.

Bednar has repeatedly maintained his innocence, arguing it was family friend Danny Cohen who killed Ms Bednar.

The 53-year-old continued that argument on Monday, as he challenged his conviction and sentence in Victoria's Court of Appeal.

Representing himself, Bednar told the court he wanted to prove his innocence because Mr Cohen had more grounds for murder than he did. 

Justice Tinney previously said the deflected blame showed a level of desperation and vindictiveness in Bednar.

But the 53-year-old on Monday said he never hurt his mother and he didn't like to talk about the numerous injuries she sustained during the attack.

"I'm just not that person," Bednar told the court.

Bednar was asked what made his sentence manifestly excessive, as his appeal contended, but he just repeated his claims that he didn't commit the murder. 

Justice Terry Forrest said the 29-year jail term with a non-parole period of 23 years seemed to be a harsh sentence. 

He noted the sentencing judge had accepted a psychiatric report that stated Bednar had delusional thoughts about his mother and a background of mental illness.

Yet the judge did not appear to take Bednar's mental ill health into account when determining the sentence, Justice Forrest said.

Melissa Mahady, representing the prosecution, argued while it was a stern jail term, it was not manifestly excessive. 

The crime had aggravating features, including the fact Ms Bednar was murdered at night in her own home, which made the sentence reasonable, Ms Mahady said.

Justices Karin Emerton, Terry Forrest and Stephen McLeish will hand down their decision at a later date.