National and Labour policies on domestic violence are still not enough to achieve the "culture shift" that New Zealand needs, says philanthropist Sir Owen Glenn.

Sir Owen, who has sunk $2 million into an independent inquiry into New Zealand's high rate of family violence, has issued a statement welcoming policies announced by National and Labour this month.

He praised National's promises to trial electronic tagging of 50 offenders and to explore a possible conviction disclosure scheme which might allow a person to be told whether their partner has a history of violence.

He supported an announcement by Justice Minister Judith Collins on Sunday that she was considering a recommendation from an expert committee to make non-fatal strangulation a separate crime because it was often an indicator of potential homicide.


He said Labour's proposals for a long-term action plan and possible alternative non-adversarial trial processes for sexual violence also have merit.

"But just imagine the political momentum New Zealand could build if all these policy initiatives, along with other political parties', were pooled in a non-partisan way.

"Most of the individual measures announced recently are useful and some of them may even have significant impact.

"But they don't represent the culture shift we need to turn around our appalling family violence statistics and also reach those many victims who are invisible in the official figures. We have got to redesign systems across the whole of our society. If we're going to manage a job as heroic as that, we all have to be on the same page, united behind a cohesive national strategy."

Women's Refuge has also launched a campaign using suffragette Kate Sheppard, "Bring Back Kate", encouraging New Zealanders to pledge to stop domestic violence.

Although Refuge chief executive Heather Henare sits on the governing board of the Glenn inquiry, the Refuge campaign calls for another independent Government inquiry into domestic violence, considering the system's response to domestic violence, and the prioritising and funding of domestic violence services.