UPDATED 3.19PM: The Prime Minister's views on gender pay have got him in hot water with a political foe.

John Key told Newstalk ZB this morning he doesn't think the pay gap is deliberate.

"Yes there is a bit of a pay gap sometimes, women tend to dominate some of the lower paid industries like carers, and there's a real issue there. But I don't think it's discrimination, it's just the occupations they are more typically involved in."

FULL INTERVIEW: Margaret Wilson - Pay discrimination

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Green Party Co-Leader Metiria Turei believes it's a disgraceful and disgusting thing to say.

"If frankly am almost speechless that the Prime Minister would be so ignorant of the importance of pay equity and equal pay in this country."

An academic also says the Prime Minister has it wrong. Waikato University's Professor Margaret Wilson claimed that "with respect to the Prime Minister, it's not always that women choice low-paying jobs; it's because there is no choice."

"Women enter the workforce, often because they have to, but also because they want to. They frequently have to take low paying jobs to fit in around childcare."

Professor Wilson maintains there is a refusal to acknowledge the importance of parents in the care of children, and enable them to support their families while in paid employment.

"It's not about choice, it's actually about the way in which we want to organise the values in our society."