New ways of presenting crime statistics, introduced last year, provided police with a more detailed picture of the relationship between offenders and victims.
"The greater the understanding of those relationships, the more we can identify ways to work with the public and our partners to address the issues."
Mr Bullock said family violence was a priority for police. It often went unreported for a variety of reasons, he said, but there had been a growing intolerance by the community.
National awareness campaigns had been a significant influence in that change of mindset.
Police were striving to foster greater trust and confidence so victims knew they would be treated professionally and with empathy, said Mr Bullock.
"Prevention remains our focus and the community can do a great deal to assist us with early intervention. We want victims to have the confidence to seek help before a situation escalates.
"That may be as simple as confiding in a friend or seeking help from one of the numerous agencies that can provide support and advice. We understand that not everyone feels comfortable with the police as the first step.
"It is also important for everyone in the community to look out for one another; to recognise when someone needs help or is suffering in silence and reach out to them or report their concerns," he said.
Nationwide 69 per cent of offenders in the 2313 acts intended to cause injury in June were known to their victims, and in 44 per cent of cases the offenders and victims were family.
Victims were known to the offenders in 38 per cent of New Zealand's 21 homicide and related offences in June. In two cases, the victim and offender were family.
In nine per cent of New Zealand's 558 burglaries this June, the victims knew the offenders. In six cases, they were family.
Women's Refuge chief executive Dr Ang Jury said police believed they saw only about 20 per cent of family violence cases.
"To encourage more reporting, we need to have victims convinced that they're going to be treated seriously when they do report and that something's going to happen."
Those concerned about relationships with family and friends should talk with police or an agency like Women's Refuge.