Police have released the names of the two children killed in Friday's Desert Rd crash.
They were Arteen Mosaferi, 4 years old, and Radeen Mosaferi, two months old, from Hamilton.
Arteen died at the scene and Radeen died at Starship Hospital yesterday from injuries sustained in the crash.
Both children were correctly restrained in car seats, police say.
Another person involved in the crash remains in a critical condition in Waikato Hospital.
The accident, which involved two cars and two truck-trailer units, happened in the Central Plateau just before 3:30pm between Waipakihi Rd and Rangipo Intake Rd.
The deaths brought the Easter road toll to four.