Their 33-year-old mother was today in a stable condition in Tauranga Hospital.
The page was set up by long-time family friends Leah and Ben Lehan to help the father travel between his scattered family.
"Due to the severity of their injuries, the children had to be transferred to other hospitals that could best meet their needs - the little girl to Waikato Hospital and the boy to Starship in Auckland," the page read.
"The father is in Auckland with his son while his wife currently remains in Tauranga hospital. Of course, this has placed additional pressure on the family at an already difficult time.
"This family needs your support, to help deal with the costs associated with bringing family together and travelling between hospitals, now and into the future, so that they can face the challenging road to recovery."