Women earn less than men because they are seen as pushovers when they don't negotiate hard and are seen as "ball-breakers" when they do, a psychologist says.
The drivers behind the gender pay gap are being highlighted by the YWCA Equal Pay Awards, which aim to recognise companies striving to tackle the issue.
Women earn 13 per cent less than men, according to the latest Statistics New Zealand income survey, despite legislation against discrimination on the basis of gender.
Awards panelist Galia BarHava-Monteith - a psychologist, executive coach and co-founder of the women's career development trust Professionelle - says "subconscious bias" is partly to blame.
When managers make decisions, such as whether to hire someone or give them a pay-rise, they often draw on stereotypes - for example, that men are authoritative and leaders, while woman are warm, motherly and enabling.
However, those stereotypes are often subconscious, which means decisions might be biased without managers realising it.
Ms BarHava-Monteith gave the example of a group of senior managers looking to appoint someone for a new opportunity involving international travel.
An ambitious, hard-working woman in her mid-20s might be very capable, but the managers could pass on her because, if recently married, they might assume she would start having babies soon.
Ms BarHava-Monteith said subconscious bias also came into play during negotiations.
"If [women] do negotiate, that goes against the stereotype that people in the room have, which is uncomfortable, and then they get judged for it."
Some employers might appreciate women who take a "gung-ho" approach to negotiations, but it could be seen as too aggressive.
"So women find themselves in a double-bind. How do you walk that fine line of not being a pushover and actually negotiating, but not coming across as a ball-breaker?"
Women in leadership positions also had to tackle subconscious bias. If they were "overly feminine" they were seen as too weak, while if they were authoritative and energetic they were seen as "bitches".
Ms BarHava-Monteith said companies should have transparent conversations about decision-making, ensure women were on selection and negotiation panels, and have transparent and systematic talent identification processes in place.
"In organisations with very robust talent management processes, women do better," she said.
Remuneration specialist Susan Doughty, who also sits on the YWCA awards panel, said bias could come into play when companies set their starting rates for men and women.
"Sometimes the decision-making is persuaded by the strength of the negotiating position to begin with ... so often you can see that a male might start higher in a pay range, rather than a female."
Ms Doughty said the managers responsible for hiring and setting pay should develop statistics around pay rates for men and women, and look at the decision-making criteria to ensure there was consistency.
* To learn more about the YWCA Equal Pay Awards and to get advice on salary negotiation skills, visit www.ywcapayequity.org.nz
