A baby had died in Wellington Hospital following a crash in Nelson last Monday, police say.
The baby was born via emergency C-section in Nelson Hospital following the crash on 30 April on Waimea Road.
It was then flown to Wellington Hospital in a critical condition, but died on Saturday.
Two other people were seriously injured in the crash and the baby's mother suffered moderate injuries.
A man, 47, was charged with careless driving causing injury following the crash.
Police said he will appear in Nelson District Court on Tuesday.
Police were continuing their investigations into the crash and said further charges were possible.
They wanted to speak to anyone who was in the area at the time and witnessed the crash.