The boy suffered serious scrapes and bruising to his chest and shoulders, and was in a serious condition when airlifted to Whangarei Hospital by the Northland Electricity Rescue Helicopter.
He was transferred to Starship Hospital in Auckland late yesterday afternoon.
It was not known whether he had suffered internal injuries or fractures.
A family member is believed to have been driving at the time of the accident.
St John Kerikeri operations manager Nick Scott said the accident was a stark reminder of how quickly young children could move.
"It's easy to lose them for a split second ... You hear of a lot of near-misses and some pretty tragic accidents as well."
The accident comes as Safekids New Zealand is launching a national campaign to reduce driveway accidents, which kill on average five Kiwi children a year.
Every fortnight a child is taken to hospital with injuries from being hit by a vehicle in a driveway.
In nearly half of all cases, the driver is one of the child's parents.
Safekids director Ann Weaver said the message the organisation wanted to get across was simple: "If someone is leaving a property in a vehicle, they need to know where their children are ... not where they were two minutes ago, but where they are right now. So often you hear people say, 'But Johnny was in the lounge. I thought he was okay.' But by the time you get to the car they can be close behind you. Toddlers can move fast and you might not always see them."
Ms Weaver said drivers should always double-check for children before moving a vehicle, as it was hard to see a small child behind the car from the driver's seat.
The months of September to April were the worst time for driveway accidents because children were outside more. Most accidents happened between 4pm and 6pm when people were particularly busy.
