Mr Hayter, a software developer, was parked across from his work in the lower AUT University parking lot at the Esmonde Rd offramp when a back window was smashed and the bags taken.
A half empty oil can in the back of the car was also taken, but a camera, GPS device and a brand new baby capsule seat were left behind.
"So obviously they're not interested in anything about babies," Mr Hayter said. "Now they've got two bags full of baby clothes and maternity bras and all the other goodies that woman have. I'm sure it's absolutely no use to them."
The Hayters are pleading for the thieves to return the gear.
"We are distraught - our baby can come at any time, and now we have no clothes or supplies for mum or baby, as everything was in the bags.
"My wife's family gave us many beautiful hand-made items when we visited them in Colombia and Costa Rica in May - these mean a lot to us and are irreplaceable."
Mr Hayter's parents, based in Whangarei, were so excited at the thought of their first grandchild that they had also given the couple a collection of special gifts.
A hand-knitted blanket made by his mum, which took years to make, was among the stolen items.
Mr Hayter said they are not interested in anyone getting prosecuted, they just want the items back.
"Please don't chuck it in the trash.
"Keep the bags, keep toiletries or whatever, but those clothes and things - people have put their hearts into [them] and people overseas have saved up money and it costs a lot more for them to give things like that."
Mr Hayter's 42nd birthday is on September 20, the day before the baby is due. He hopes to receive an extra special present this year.
"It'll be the most amazing gift of my lifetime ... I would've waited 42 years for it."
Even better if the baby gear is returned, he said. "If they can hand them in to the NZ Herald, or any police station, we'd be extremely grateful."
One of the bags is a blue Nike duffel bag and the other is an adidas black and orange bag of a similar style.
Senior Sergeant Mick Rickards, response manager of North Shore Police, confirmed that a car was broken into on Monday while it was parked at the AUT campus on Akoranga Drive.
"Police have forensically examined the car for fingerprints and are waiting for those results. At this stage though there are very limited lines of enquiry," he said.