"Employers who have been forced to bear considerable replacement costs, or to find those amongst their other employees willing to provide cover, may well think hard before again employing a woman of child-bearing age."
After his submission, Mr Mackay dug himself into a deeper hole by comparing women on maternity leave to rugby players.
"If you're a rugby player and if you don't play for six months, you're rusty so the chances that you'll make the top team on the first day are not high. It's that sort of proposition where you're losing your sharp edge, your immediate availability, your immediate effectiveness diminishes if you're not engaged in the activity at the time." he said.
Mr Mackay's comments have, predictably, sparked outrage including from the director of Zonta Club Hawkes Bay Ailsa Allen, who rejected the claim.
After the furore he created, I am sure Mr Mackay is wishing he had not said what he said or, at the very least, said it slightly more tactfully.
Mr Mackay is on a slippery slope with this one. I just don't think extending maternity leave would put companies off hiring young women just in case they get pregnant. Most savvy bosses are prepared to cut good employees some slack because they know the kindness will be repaid by hard work.
The time for a mother to spend with her newborn child is important and it is better to have a valuable worker come back to work having spent quality time with her baby. A woman who rushes back to work afraid she has limited her career prospects by having a baby is justifiably going to be more stressed than one who takes more time.
Obviously there are cost implications, but then again skilled employees are worth waiting for and worth the expense.