A report from British Columbia's children's watchdog into the murders of three young children at the hands of their father says there were serious failures on the part of the provincial Ministry of Children and Family Development.

Mary Ellen Turpel-Lafond's report said the children's deaths could have been prevented if the province's social safety net was properly implemented.

The report's release prompted an immediate government apology to the kids' grieving mother.

Ten-year-old Kaitlynne Schoenborn and her brothers, eight-year-old Max and five-year-old Cordon, were killed by their father, Allan Schoenborn, in Merritt, B.C. in April 2008.

He left their bodies to be found by their mother, Darcie Clarke, the next day. He was later found not criminally responsible for their murders because of his mental state.

Turpel-Lafond said the loss of the children is heartbreaking because it was preventable.

"The Representative believes that Kaitlynne, Max and Cordon's right to safety was compromised by a lack of collaborative, professional child protection practice," her report said. "MCFD failed to appropriately meet its mandate to protect children. Gaps and shortcomings in the mental health system similarly failed this family."

Premier Christy Clark formally apologized to Clarke in the legislature, saying the province must do better to protect children.

"I got back into politics because I wanted to make sure our province was doing a better job supporting families," said Clark. "It is clear today government must do more."

Turpel-Lafond says the B.C. government needs to understand the risks that children face with a parent dealing with mental illness and called for a more co-ordinated approach to child protection.

The 130-page report also says there was ineffective management of the Schoenborn's case, in part because when the family moved the case transfer process didn't work.

The report blamed not only case supervisors but new, inexperienced employees as well.

"There were inexperienced workers in both communities who were not trained to work with high-risk families with multiple, complex needs," it reads.

The report didn't just place blame on the child protection agency, but it also pointed to serious faults in the criminal justice system.

"The policies and practices of the criminal justice system were inadequate in protecting the children and their mother from the continued influence and violent behaviour of the father, and they require improvement and immediate attention," the report found.

A case was brought against Schoenborn for the sexual assault of the children's mother, but when she retracted the statement, the case was dropped.

The report says there was a missed opportunity by victims' services to assist the mother.

Children's Minister Mary McNeil said her ministry will establish a domestic violence unit to work with a new government committee that aims to develop an action plan to support children and families hurt by domestic violence.

McNeil acknowledged the new domestic violence unit currently does not come with new government funding, but that may change as the government develops a new action plan by July 31.

With files from The Canadian Press