A third of companies on the stock exchange's main board have no woman directors, while another third have just one, new figures show.
Earlier this week, information filed by NZX-listed companies showed 17 percent of directors last year were women, averaged across each quarter.
The figure is the same as 2015, and for the final quarter of 2016, the percentage fell to 13 percent.
The Institute of Directors has investigated further and found, out of 120 companies, only one has a female chief executive, and seven have female chairs.
It found 41 companies have no female directors, while 35 have only one.
The institute's governance leadership centre manager, Felicity Caird, said the figures were "shocking" and "clearly not good enough".
"We were really surprised when we did this last year for the first time that there were 39 companies that had no female directors and that number is now 41," she said.
"The lack of change is really concerning."
An attitude change was desperately needed, she said.
"It's a cultural change that does take time, but it really requires commitment and leadership from the boards themselves and we've been working with them to drive a change in diversity.
"When we surveyed them last year, 70 percent said they thought diversity was important."
Trying to force change by introducing quotas was not the answer, she said.
Instead, unconscious bias needed to be better addressed and more work needed to be done identifying diverse talent.
Information from the institute showed New Zealand's rate of female directorships was even worse than other western countries.
In Canada the percentage was 21 percent, in the UK 27 percent, and in the US it was 22 percent.
The former chief executive of Telecom, Theresa Gattung, said she was "flummoxed" by this country's severe lack of female directors.
"I see companies where the male chief executives are actively working to develop their female talent and are actively trying to hire women, but collectively we have to agree it's just not good enough," she said.
"It's many years since I was a CEO and I'm flummoxed as to how there is still such a paucity of women in top roles."
She said she has always been against quotas, but was becoming more open to them as the gender imbalance persisted.