They cross a bridge during their drive and at one point the girl tells the driver to "go slow". Grass fields can be seen outside and what appears to be a quiet country road.
The 58-second clip was uploaded to media page Paint Fade on Tuesday.
Facebook user Merf Ayebro claimed the driver was his son.
"My son is the man country life learn how to drive at a early age !!!" he says.
He added: "This aint new in the country life seen kids 8 an upwards driving like it aint nothing now most of them no how to operate machines an they still in there teens country road where hardly no cars are we can teach them but city hell no he wont be doing this !!"
On Tuesday he said the video had had 77,780 views, adding: "When ur kids get more views than u ever since i been on facebook hahaha and thats not even 24hours yet lol".
The footage has sparked hundreds of comments on unsafe driving and foul language.
But many of those weighing in on the Paint Fade account suggested it was normal for children who could barely see over the steering wheel to drive on country roads.
"... Yes our kids learn from the age of 4 to round up the cows on motorbikes and from there tractors, then cars. Then they learn how to fix them as well as pig hunt, tame horses and live off the land. Best upbringing and wouldn't change it for the world. Country life is best," one wrote.
"I'm sure if you were in that situation having that much fun, you'd throw some swear words around too. and with those driving skills I think he earned it," Seraiah Herbert Chase wrote.
"I think it's gorgeous that the kids learn to drive at a young age, wish I had a child hood of rounding up sheep and going for bike rides in the country with friends," Lucy Cahir said.
Other users were appalled at the absence of seatbelts and the childrens' swearing.
The footage was reportedly shot in Northland.
The driver appeared to be of primary or intermediate school age.
In New Zealand a person must be at least 16 years old to get a learner licence.
