Lorelle Thiess, 59, was last seen at her home in South Street, Gymea, on Saturday.
Her dark blue Mazda 3 sedan was found parked in Prince Charles Parade, Kurnell, shortly before midnight on Sunday.
Her personal possessions had been left at her home.
Police today said a large search had resumed in the Kurnell area after they found no success yesterday at Sydney's southern beach suburbs, local hospitals and medical centres.
The search involves local police, the police helicopter, Polair, the Westpac LifeSaver, Rural Fire Service (RFS), State Emergency Services (SES), as well as local bushwalking search and rescue volunteers, a police spokesman said.
"Given the area, it makes it a little bit difficult, because obviously you've got bushland and beaches there, so that's probably why it's such a large search," he said.