The country's business leaders should "hang their heads in shame" if they do not have a woman on their board, former Equal Opportunities Commissioner Judy McGregor says.
The latest census of women on New Zealand boards found that they hold just 22 percent of all directorships in the top 100 NZX listed companies, and a quarter of those companies have no women on their boards at all.
Professor McGregor, who led the research at AUT, told Nine to Noon New Zealand was "absolutely lousy in terms of corporate governance".
"It's the NZX, I think, they're the publicly listed companies that investors should be taking note of whether or not there is gender diversity on the board," she said.
"They should be concerned about that. They're the companies in the spotlight all around the world."
You can read the full report here.
A step-change was needed to achieve gender balance in the boardroom, because a reliance on goodwill and voluntary encouragement had resulted in painful, incremental progress, Professor McGregor said.
The NZX has recently introduced new rules which meant listed companies needed a gender policy, and an explanation if they did not, she said.
Investors, consumers and employees should exert pressure on 25 companies in the top 100 that have no women on their boards, Professor McGregor said.
"There is ample evidence that there is no supply problem.
"The Ministry for Women's nominations service has banks and banks of talented and competent women who have been placed on government statutory boards - they've already got governance experience.
"There are many many women who may be untried but have governance ability who simply don't get through the door," she said.
However, the gender-balance numbers in New Zealand were not all bad, she said.
"Ironically, we're incredibly good in terms of appointments to government statutory boards.
"We're well above 43 percent , some of which [boards] are hard to manage and hard to govern.
"That's fantastic work by successive government administrations," she said.