Justice system failed stepdaughter: mum

The family of a woman allegedly killed by her partner at a Melbourne shopping strip says the justice system continues to fail women and children.

Simone Warzywoda says the family has been touched by the community's kind words, donations, flowers and prayers in the wake of her stepdaughter's death.

Mother of four Fiona Warzywoda, 33, was stabbed to death in front of lunchtime shoppers at a Sunshine retail strip last Wednesday.

Surrounded by Fiona's two sisters Karen Kelcey and Jazmyn Warzywoda, Ms Warzywoda said the tragedy had touched many and the family asked for privacy during what was an emotional time.

"On behalf of the family I express my deepest gratitude for the support, kind words, donations and flowers and prayers," she told reporters at Sunshine on Tuesday.

"We understand it has affected the community as a whole and this tragedy has touched many of us."

Ms Warzywoda said the system had let down her stepdaughter.

"As it has been time and again with domestic violence, the justice system continues to fail women and children," she said.

The family is working to set up a fund to receive donations.

Fiona Warzywoda's de facto partner of 18 years, 38-year-old Sunshine North man Craig McDermott, has been charged with her murder.

The murder allegedly occurred after they were in court over a family violence order, the Melbourne Magistrates Court heard on Thursday.