"Once we moved back to New Zealand my wife was in a position to earn more money than I could so we just went with that. It was what I wanted to do and my wife's role made it happen. It made financial sense," he said.
"The actual staying at home and looking after the kids was a bit of a no-brainer. I believe there's quite a few men out there doing it."
Mr Grimshaw has been principal caregiver to the Te Puna couple's two youngest daughters for nearly five years.
"It's been a learning curve, that's for sure. The girls do swimming and dancing. I take them to school, I pick them up, I do the shopping, in between that there's the housework inside and outside.
"A lot of the house chores I never thought I'd do, like cleaning the toilets. The biggest thing to get my head around though is not being able to be so productive. You're constantly having to drop things to look after the kids, so trying to get things done around the house is not as easy as one would think. There comes a certain time in the day when you've got to down tools and start getting dinner ready."
He said he had enjoyed forming a closer bond with his daughters and had "learned to be a lot more sympathetic with the little ones".
"We have the odd friend's wife having a bit of a laugh about it now and again, saying that I get to stay home and watch all the soaps, but it's not quite like that," Mr Grimshaw said.
"Growing up in your younger years you don't really think of it as a fulltime job but once you get into the role you understand how full-on it is."
Mr Grimshaw said he would be doing the role for the foreseeable future.
Marie Grimshaw is NZ site projects manager at Orica Projects, in Mount Maunganui.
"I think traditional views are changing," she said. "If it makes sense for your family then why not? It's worked out really well. The kids love having him around and they get to do more things like kayaking and fishing, which they wouldn't if it was me at home.
"We have a lifestyle block and so he does the manual things as well, the fencing, shearing the sheep, moving cattle, all the heavy lifting. There's been some adjustments, like Peter learning how to plait a girl's hair, doing buns, getting them ready for dance, that sort of thing.
"He hasn't gone to any daycare groups or anything but he probably would, he's pretty sociable. When the invites come they're female-oriented of course, like a mum's morning tea, which obviously is not so appealing to him. I'd be a bit worried if it was."
Mrs Grimshaw said when the family was in Australia they knew of three other dads who were undertaking the home role.
Anecdotal evidence locally suggests the number of those husbands remaining at home to raise their children is on the rise.
Phil Van Syp, managing director of 1st Call Recruitment in Tauranga, said his company had seen an increased number of men looking for work after a period of parental leave in recent months.
The Grimshaws' Te Puna neighbours, Kelvin and Sally Hargreaves, have three young children, Danielle 8, Ben, 5 and Alex, 3. They had made a similar choice, said Mrs Hargreaves, who is principal engineering geologist at Tauranga's Coffey Geotechnics (NZ) Ltd.
"When Kelvin was first at home he was telling people he had retired because he wasn't doing the 9 to 5. But he completely underestimates the amount he does," she said.
"Kelvin was a mechanic and that is hard work and underpaid, so he was never going to be earning the big bucks. By the time we had the second child, putting two children into daycare and Kelvin working just didn't make sense. We were about $10 a week better off. So that's when we made the decision for him to stay at home.
"It just takes a lot of the stress out of the day. If you're both working you get home at the same time with hungry kids, the house in a mess, laundry still to do. I really enjoy being able to come home and things are done. I'm the messy one and he's the neat freak so it wouldn't work the other way round for other reasons.
"It makes a difference to our free time too. With everything done it means we can do more things on our weekends."
The children were benefiting from having their dad around, said Mrs Hargreaves.
"They are more practical and self-reliant and that's been commented on at school. Whereas mums at home might do more things for them straight away, a dad might say 'well you can do that yourself'."
The family also lives on a lifestyle block and Mrs Hargreaves described her husband as "a very hands-on, practical guy who gets on with mending fences, looking after the cows, building and renovating things".
However, she can't see her husband attending daycare groups: "I don't think it's quite reached that stage. That sort of thing is not Kelvin's cup of tea."
