Annabelle was pulled from the wreckage of her family car still breathing, however she has since died in the Intensive Care Unit at Liverpool Hospital, in Sydney, this morning.
The young childcare worker was on her way home from Christmas celebrations with Jessica and their parents when their car was involved in a head-on collision.
The father of the girls, Lars, aged 69, and mother Vivian Falkholt, 60, were killed instantly in the crash while the driver of the other vehicle, Craig Anthony Whitall, 50, also died in the inferno.
Speaking to Daily Mail, a relative revealed the family had been called in to gather around Belle's bed on Friday morning to say goodbye.
'Annabelle passed away this morning, we knew what was happening so family were with her,' the cousin said.
'Her and Jessica had such a strong sister bond. They are seriously close sisters I feel Jessica would have known her sister passed.'
Sending love to the family members during this difficult time.