Sydney grandmother 'was sweetest person'

The distraught family of a great grandmother who died following a suspected hit and run in Sydney is pleading for the driver to come forward.

Jean Harrison, whose family had all gathered at her home on Sunday to celebrate her 83rd birthday, was found lying in the middle of a street near her home in Sydney's southwest suburb of Miller around midday on Tuesday.

The mother of seven, great grandmother and grandmother to more than 20 was treated by paramedics and transferred to Liverpool Hospital but died overnight with family by her side.

Mrs Harrison had headed to the local shops on Tuesday morning and was walking home when she was hit, her family said.

They've described her as being very independent.

They say she was crossing the road when she was hit.

"She had just turned 83, she lived in that area, everybody knew her. She would have done anything for anybody," granddaughter Louise Hird, told the Seven Network.

"She was beautiful, she was the sweetest person.

"I'm sure (the accident) wasn't on purpose but they need to be responsible for what they did `cause imagine if this was their grandmother and they just had to witness her laying there on life support and watching her slip away."

Police are continuing to investigate and have appealed to the public for information.