Craig McDermott threatened to harm the mother of his four children the day before he fatally stabbed her outside her solicitor's office.

Overheard by a court security officer, the forewarning could have prompted more action to prevent Fiona Warzywoda's untimely death.

Fiona Warzywoda was fatally stabbed by her partner in Sunshine. Credit:Supplled

A coronial finding released on Thursday in fact identified several "missed opportunities" before Ms Warzywoda was murdered by her former de facto of 18 years.

Coroner Audrey Jamieson noted the shortcomings were already addressed in changes recommended by the royal commission into family violence.