A man who claimed he stabbed his former partner six times in broad daylight outside a Sunshine shopping centre in self-defence has been found guilty of murder.

Craig McDermott, 39, showed no emotion as the jury of five women and seven men unanimously found he had murdered Fiona Warzywoda, 33, a day after a court refused him access to their children

McDermott had told a Supreme Court jury that Ms Warzywoda, the mother of his four children, was the one armed with the knife and he had only wanted to speak to her when she was returning to her car after seeing her solicitor.

In court, Ms Warzywoda's family members broke down in tears as the verdict was read.

McDermott had denied having minutes earlier bought a knife from a nearby shop or having ever been armed with a knife when struggling with Ms Warzywoda, his former partner of 18 years, and stabbing her six times on April 16, 2014.

Crown prosecutor Brendan Kissane, QC, had told the jury McDermott had murderous intent when he confronted Ms Warzywoda in broad daylight in front of dozens of shoppers.

"Clearly this was not an accident," Mr Kissane said.

"If you stab someone six times, you intend to kill them ... and you don't stab somebody six times believing that it's necessary to do that to defend yourself."

Mr Kissane said a pathologist gave evidence about each of the stab wounds, including how two were fatal stab wounds to the chest and the others to different parts of the body.

The prosecutor pointed to evidence from eyewitnesses about how Ms Warzywoda was screaming when being chased by McDermott who had been keeping watch for her at a nearby cafe.

One witness described the incident as being like a cat chasing a mouse.

Mr Kissane said Ms Warzywoda had been to the magistrates' court earlier that day to obtain an intervention order against McDermott and the pair had left the court at about the same time.

Ms Warzywoda then went to her solicitor's office as McDermott lay in wait.

One witness claimed the stabbing was ferocious after McDermott had rugby tackled Ms Warzywoda to the ground.

Another witness claimed Ms Warzywoda was lying on the ground on her stomach when McDermott rolled her over and stabbed her in the chest the first time.

McDermott and Ms Warzywoda had been together for 18 years and had had four children but their relationship ended in February 2014 after a family party.

McDermott had been drunk and abusive at the party after being told to leave and smashed the window of Ms Warzywoda's car on his way out.

He later allegedly told one of the couple's children that he was going to kill Ms Warzywoda with a pocket knife he kept in his car.

Another witness claimed McDermott vowed he was "going to slice her".

Ms Warzywoda told people on the day she died that she was in fear of McDermott and how he had confronted her and told her, "You're f--ked."

Defence barrister John Desmond told the jury it was not far-fetched to suggest Ms Warzywoda had been carrying the knife.

"This is a very graphic physical incident where the deceased has been stabbed six times in broad daylight, public thoroughfare in front of umpteen numbers of people," Mr Desmond said.

"One could easily jump the gun and say it's got to be murder. But it's jumping the gun.

"If it is correct that Fiona had the knife and came at him with it, thrusting it forward, any objective measure of the situation begins to point to a conclusion that it may not be murder.

"Because a person is entitled to defend him or herself."

Mr Desmond said McDermott largely had no memory of what happened from the moment he tried to deflect the knife away from him and grabbed Ms Warzywoda's hand holding the knife.

McDermott will be sentenced at a later date.