The children's parents were injured in the collision, which involved four cars.
Their mother, Dr Mohadeseh Sharifi, was critically hurt and their father, Siamak Mosaferi, had moderate injuries.
The Herald reported at the time that the family was understood to have been heading to Wellington for the Easter break with friends when their vehicle collided with the truck.
Two truck-and-trailer units and another car were involved and all vehicles were heading south when the incident happened at 3.27pm.
The crash happened on a straight stretch of road between Waipakihi Rd and Rangipo Intake Rd.
Police told the Herald in the days after the crash that a truck driver was also injured. It is not clear whether the injured person was the man who has been charged.
Four days after the crash police appealed for witnesses to the crash to come forward.
Arteen and Radeen's deaths devastated their tightknit Hamilton community.
A neighbour, who lived across the street from the family and was "very close" to them, said they moved into the quiet cul-de-sac nearly two-and-a-half years ago.
Mosaferi and Sharifi were "amazing" parents who often watched over Arteen as he played in their driveway.
"They're wonderful neighbours. They're amazing, it's just too cruel. It's affected us all around here. We're all very close."
The couple migrated to New Zealand from Iran in 2009.
Sharifi gained a Doctorate of Philosophy studies in Chemical Engineering in 2012.
Mosaferi completed his Master of Engineering Degree at Auckland University in 2013.
Mosaferi's employer Tony Wade described him as "a hardworking and valuable member of our close-knit family orientated business".
"[He] is an active participant in office social events and a proud family man."
The crash was one of three on New Zealand roads during Easter Weekend.
The same day, in Tirohanga, between Pokuru and Tirohanga Rds, north of Taupo, local woman Denise Tito died in a crash.
On the Saturday morning, a person died after a motorcycle and truck collided in Rotorua.
Horrified crash witnesses said the motorcycle lost control and went under the truck's wheels.
The motorcyclist died at the scene despite frantic efforts from members of the public to resuscitate him.
