Former NZ basketballer Phill Jones said the couple had found having two children "kind of easy" so decided to have a third.
"Our friends are having kids at the moment," he said. "They have just started their families; I think they might look at us and see three and see we've handled it pretty well and it may be something they think about."
Other parents of three include actress Greer Robson, newsreader Wendy Petrie, TVNZ Breakfast host Petra Bagust and her predecessor Pippa Wetzell.
From 1996 to 2006 the average number of kids in a family hovered just below two. But now the figure could be rising as parents decide bigger is better.
Already, the Herald on Sunday has revealed, primary schools in well-to-do suburbs like Ponsonby, Grey Lynn and Westmere are dealing with a baby boom. They are being forced to bring in pre-fabricated classrooms or expand on to adjacent properties.
Education Minister Anne Tolley has commissioned a demographic report as new entrant numbers are projected to rise from 57,815 last year to 65,070 in 2015.
With the postponement of this year's census because of the Christchurch earthquake, Statistics NZ does not have up-to-date figures on the number of children in families.
But many maternity workers agree: larger families are becoming more common.
Auckland independent midwife Rhondda Kerrins, who has 37 years' experience in the field, said more women were opting to have three children.
This month alone, three of her mums gave birth to their third child.
Kerrins said parents sometimes wanted another child after their first two had started school. Or, if they already had two of one sex, they might try for one of the other sex.
"I've got quite a few having three or even four," she said. "It's not unusual any more. It's on the way up."
Dr Chern Lo of Birthright Obstetrics said that in the past year she had noticed more parents starting families in their late 20s rather than late 30s.
"The generation in their early to late-20s are planning to have more than two children."
Dr Martin Sowter, from Auckland Obstetrics Centre, said he too had noticed a trend towards bigger families.
"Over the past four or five years there are certainly more people comfortable with having three rather than two," he said.
Auckland psychologist Sara Chatwin said many parents wanted to move away from the typical "ideal" family by having three children.
For many, she said, a family didn't feel "complete" until the third child was born.
"The two-child family was a bit too perfect," she said.
MAGIC TO BE OUTNUMBERED
Three is certainly "the magic number" for Philly Irvine. The stay-at-home mum and her real estate husband, Tim, are parents to Benjamin, 9, Toby, 8, and Edward, 4.
The Herne Bay couple didn't feel their family was complete until they had three. "Two never felt quite enough," she said.
And most of their friends chose to have three rather than two children, she said.
Having three active boys made for a busy family life and, although raising children was expensive, they wouldn't have it any other way. "One of the things we love as parents is that we're outnumbered. Three is quite a magical number."
The couple were careful about their spending, especially on groceries and clothes, so they could afford family holidays and the boys could enjoy extra activities.
Like most siblings, they either got on well or fought "like cats and dogs".
