But McLean, who is part of a business group which champions diversity in New Zealand businesses, described the questions as appalling.
"I find it appalling that in 2017 one of the first questions asked of a new leader who is female is about her plans regarding having children.
McLean said he could not remember any male leader in business or politics ever being asked such a question.
He said a person's intentions around parenting were their own business and no-one else's.
"The role of the employer should be to find ways to allow their employees to have a full personal and family life and bring their best to work."
More than half of the management positions at Westpac were held by women and 65 per cent of its staff were female, he said.
McLean said it had explicit policies around asking staff about future children.
"We will never ask anyone about future plans for parenthood... that should never happen, either in senior management roles or any other positions."
Westpac was a flexible and family-friendly workplace which had a wide range of initiatives, including a graduated return to work for staff returning from parental leave and contributions to school holiday programme fees, that were available to both mothers and fathers.
The Human Rights Commission advises employers against asking questions related to "pregnancy, proposed pregnancy, contraception or family planning, or parenthood".
"These types of questions risk breaching the act as they could be seen as indicating an intention to employ, or not employ, applicants based on whether they're responsible for children or not."