The New Zealand stock exchange is introducing a new rule requiring listed companies to disclose how many women they have on their boards and senior management.
The diversity rule, which requires the approval of the Financial Markets Authority, will apply to the annual reports of companies with a balance date on or after 31 December.
In addition to publishing a breakdown of directors and senior management by gender, firms with a formal diversity policy will be required to evaluate their performance with respect to that policy.
NZX chief executive Tim Bennett says only 9% of companies listed on the New Zealand stock exchange have female directors compared to 17% of firms on Australia's exchange.
He says the mandate of NZX is to grow the country's capital markets and evidence shows that shows gender, ethnic or age diversity among senior executives and in boards drives business performance.
"If you're a board or a senior management team that has a reasonable number of women in that group you realise that you get a lot more debate, you get a lot more thinking and you get better outcomes."
NZX says listed firms will make their own call on whether they need a formal diversity policy, and will not make it mandatory, but is urging them to do so to help investors.
Institute of directors support
The Institute of Directors says the new stock exchange diversity rule will help New Zealand catch up with Australia in regards to the number of women on company boards.
It has launched a mentoring programme to help more women get onto boards.
Chief executive Ralph Chivers says about 17% of Australian listed firms have female directors compared to about 9% in New Zealand but the new rule could help close that gap.
Joan Withers is chair of Auckland Airport and Mighty River Power but she is a relative rarity in this country.
She says she hopes the new rule will get companies to focus on diversity.
"I started my governance career about fifteen years ago and I certainly would have anticipated that by this stage there would be a greater percentage of women on boards. So I think the focus now is appropriate, I think it's a matter of making sure that companies are focussing on diversity generally."
Ms Withers says New Zealand should be aiming to have women making up 25% of board members by 2015.
And a group working to increase the number of women in senior management and board roles is aiming for just that.
A dozen of the country's most influential business leaders formed the 25 Percent Group this year, setting a target of at least 25% of women overall on New Zealand's boards by 2015.
One of the group's founding members and the chairman of Vector, Michael Stiassny, believes the new rule will help put pressure on companies to recruit more women to top level jobs.