A government committee looking into the cause of deaths as a result of family violence hopes eventually to analyse every case where someone is killed by a family member.
The Family Violence Death Review Committee, set up in 2011, has released preliminary findings from the first three cases it has reviewed.
The committee talks to agencies involved in cases about how they responded and what could have been done better.
Its initial findings suggest that the Department of Corrections should consider family violence when offenders are released.
It also recommends that maternity services liaise better with Well Child services such as Plunket and that police are better trained to detect family violence.
The committee's chair, associate professor Julie Tolmie, says it hopes to review eight cases this year and set up regional panels that will eventually begin reviewing cases.