Vojneski, 32, was sentenced to life in prison in 2014 after a jury found him guilty of stabbing his girlfriend, mother-of-three Paula Conlon, 30, to death one night in March 2012.

Ms Conlon's body was found in a bedroom of her Macgregor home. She had suffered 15 knife wounds.

He was last year granted the right to challenge the conviction and sentence in the ACT Court of Appeal on the grounds some evidence may have been wrongly admitted at the trial.

Vojneski's defence barrister, Shane Gill told an appeal hearing on Monday the inclusion of several incidents from Vojneski's past involving knives had "painted him as a knife-wielding psycho", unfairly prejudicing the jury against him during his trial.

"The issue at trial wasn't if he threatened Conlon with a knife, it was that he stabbed her," Mr Gill said.

"Your honour is conflating getting a knife with using a knife.

"That's part of the evil of tendency evidence in this case. There are three other incidents where he's applied the knife [but only] one incident where he stabbed someone."

In several of the instances Vojneski had made threats to stab but didn't follow through, the court heard.

In the one instance where Vojneski had stabbed someone Mr Gill argued there was no evidence he was angry or intoxicated at the time and in another incident when he was angry and under the influence he stabbed his neighbour's tyres, not a person.

"Paula Conlon was not an object, she wasn't a car tyre," Mr Gill said.

"[Vojneski was] ruffed up by his neighbours, despite that he did not stab the neighbours he stabbed an inanimate object."

But Chief Justice Helen Murrell said the tendency evidence was just one piece of circumstantial evidence used in Vojneski's trial.

She said there were "plenty of other relevant circumstances" including evidence Vojneski was at Ms Conlon's home earlier on the night of her death and the couple had argued.

She said in three of the incidents Vojneski had grabbed a kitchen knife, as had t occurred when Ms Conlon was stabbed to death.

But Mr Gill said there was nothing significant about someone grabbing a knife from the kitchen and much of what the incidents sought to prove was "common to humanity", including Vojneski's tendency towards anger-fuelled violence while intoxicated and his knife use.

He said an incident involving Vojneski punching his mother in the face had unfairly painted him as a "monster" and poisoned the jury against him, but did not prove his tendency to use a knife.

Chief Justice Murrell acknowledged the bench did not think the inclusion of the assault had much value as evidence against Vojneski.

In response, Director of Public Prosecutions Jon White argued in his submissions the tendency evidence had probative value.

He said there was no doubt the trial judge had turned his mind to the matter of prejudice in allowing the prosecution to lead evidence of Vojneski's violent tendencies at trial.

Submissions on the appeal against Vojneski's sentence are yet to be heard.

The hearing continues on Tuesday.