A new requirement for listed companies to have a comprehensive diversity policy is expected to help the country tap into our talent pool.

Companies like Air New Zealand, Fonterra, Sky, Spark, Xero, The Warehouse, Westpac and Fletcher Building must now have a comprehensive, written diversity policy in place, with measurable goals.

Global Women deputy chair Joan Withers told Rachel Smalley it's not saying you have to have X percent by X date.

"It's just saying that investors and wider stakeholders need to understand each company's approach to diversity, because the research is irrefutable. Diverse boards perform better."

She said she has never had a problem finding very skilled women across all areas, even engineering.

Withers said she's against quota systems because they're demeaning.

She said all the women she works with on boards are there because of their competence, and can hack it with any of the male directors.

"This is saying look, we need to be utilising as a nation the whole talent pool that we've got."

Withers hopes private companies will follow suit.

LISTEN TO THE FULL INTERVIEW WITH JOAN WITHERS ABOVE