Search for elderly Sydney woman continues

The search for an elderly woman who has been missing for three days in NSW bushland will be scaled back overnight, as rescuers battle adverse weather.

It's believed Gaida Coote drove to the Ku-Ring-Gai Wildflower Garden at St Ives in Sydney's north about 9am on Wednesday.

Authorities were notified on Friday when the 84-year-old didn't return.

Rescuers on Saturday afternoon began to scale back their search as heavy cloud cover and rain set in.

Police say the weather may affect the search on Sunday.

"It will depend largely on how things are weather wise, who is available and how safe that area is to search," a police spokesman said.

Police dogs joined the search for the woman on Friday, before that search was suspended at 8pm due to stormy weather.

Her car was found in a nearby car park.

Mrs Coote is described as being of Caucasian appearance with a thin build and short wavy grey hair.