Emergency providers had been known as to a house on Weston Avenue, Revesby simply earlier than 8.50pm on Saturday the place they situated the pair, aged 36 and 48, inside a automobile.
NSW paramedics tried to save lots of the 48-year-old nonetheless she died on the scene.
The 36-year-old was taken to Liverpool Hospital in a crucial situation, the place she later died.
A person and a lady, who had been unhurt, had been additionally contained in the automobile on the time emergency providers arrived.
An investigation into the incident is underway and a criminal offense scene has been established.
It's not identified if the incident is linked to latest gangland shootings in Sydney.