The Safe Kids group says people need to increase their awareness of children on driveways to prevent more deaths.
Police are investigating the death of a toddler, aged one year, who was run over on a driveway near Warkworth on Monday.
Safe Kids said that makes four such deaths since November. The group said five children are killed by cars on driveways on average each year and about one a fortnight is hospitalised.
Safe Kids said parents and close relatives are most often the ones behind the wheel.
Director Ann Weaver said most of the incidents are preventable.
She said parents need to check for children when using the car, make sure children are supervised and put up fences.