Homicide detectives have confirmed there was a restraining order out against the killer, and that he had a history of domestic abuse against the woman.

The Melton West woman, 33, had been at Sunshine Magistrates Court on Wednesday because of a dispute with her de-facto husband of 18 years. She then went to a nearby women's refuge and to her solicitor's office on Hampshire Road, Sunshine.

Three minutes after walking out the door, her de-facto husband, 38, of Sunshine North, stabbed her multiple times in the chest with a fishing knife, according to police.

''It's an atrocious crime,'' Detective Senior Sergeant Stuart Bailey said.

''The offender is known to police, has a history of domestic violence and also his own history of violence.''

The killing happened in front of the man's son, aged in his 20s.

Police cannot, for legal reasons, confirm the nature of the court dispute believed to have led to the brutal killing.

''We were hoping the dispute would be resolved by the court itself, but this de facto has taken it into his own hands to try and resolve it in his own way, and it escalated and she has been fatally stabbed.''

The woman died in the middle of a suburban shopping strip at the corner of Devonshire and Hampshire roads, after several onlookers tried frantically to revive her.

She was pronounced dead shortly before 12.30pm.

Senior Sergeant Bailey said the killer fled in a red Holden sedan, driving west down Devonshire Road, before crashing into another car and fleeing on foot.

Police found the getaway car and have launched a manhunt in the area involving the police air wing.

The knife was found near the dumped car on Foundry Road.

The man remained on the run on Wednesday night.

He is described as 175 centimetres tall and slim with short-cropped hair and a goatee. He was wearing a black hoodie, black jeans and blue runners.

Witnesses to Wednesday's killing told of their horror at seeing the woman, who several say appeared pregnant, stabbed to death in broad daylight.

Vu, the owner of a restaurant at the busy intersection, said he believed the woman was pregnant.

Real estate agent Anjana ran out from her office when she heard screaming. ''There was a lady bleeding … a lot of blood,'' she said.

Victoria Police figures obtained by Fairfax Media reveal more than 820 offenders, overwhelmingly men, breached intervention orders at least three times in the past financial year.

Of these, 200 individuals violated orders more than five times and 15 committed more than 10 separate breaches in one year.

The courts have had to process a record number of breaches, which topped more than 12,000 last year.

Victoria Police has repeatedly blamed rising crime rates on family violence offences, with special teams dedicated to the most problematic cases in recent years.

With Jane Lee