An inquest into the death of Noeline Dalzell is investigating how police and other state government services failed to protect her, and their three teenage children, from James Fairhall despite a long history of family violence.

But police say changes have been made since her death.

Victoria's State Coroner John Cain heard Ms Dalzell met Fairhall in 2002 and their relationship turned violent quickly, escalating further following the birth of the couple's third child.

Fairhall was in and out of prison, due largely to family violence offences against Ms Dalzell and their children, and he was banned from contacting them.

Fairhall was let out of prison at the end of 2019 and 13 days later a warrant was issued for his arrest.

But the warrant was never executed and Fairhall moved in with Ms Dalzell and their three children, telling them he had nowhere else to go.

He slept on Ms Dalzell's couch until he killed her on February 4, 2020.

On that day their children returned from school to find their parents arguing.

Fairhall was jealous and enraged about his ex's new relationship, when he followed her through the home holding a knife.

He reached over their children to inflict a fatal stab wound to Ms Dalzell's neck, before their son intervened and tackled Fairhall to the ground.

She ran to her neighbour's home, where efforts to save her failed and she died at the scene.

Victoria Police Assistant Commissioner Lauren Callaway, who leads the family violence command, said Fairhall's release from custody took police and corrections by "surprise" given his long history.

She said his transient lifestyle and active avoidance of police made it hard for officers to track him down, despite numerous calls to Crime Stoppers between his release and subsequent arrest.

Every time police turned up at Ms Dalzell's home, she said he wasn't there.

"It's difficult to engage with someone who's actively avoiding you," Ms Callaway told the court on Monday.

Judge Cain questioned what value had been added to processes since Ms Dalzell's death, and whether there might have been a different outcome had those changes been in place in 2020.

Ms Callaway stopped short of saying the result may have been different.

But she conceded the calls to Crime Stoppers would have made his arrest warrant a higher priority if it were to happen today.

She said there were some "really good practices" in place, including a monitoring and evaluation plan that goes all the way up to state level and additional family violence liaison officer shifts.

Fairhall was found guilty of murder and sentenced to a maximum 25 years' jail.

Ms Dalzell's brother Malcolm and sister in-law Jennifer were in court for the inquest hearing, which continues on Tuesday.

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Australian Associated Press