A wife has pleaded with the public to help find her "lovely husband" more than two days after the Alzheimer's disease sufferer wandered off.
More than 100 people on foot, horses and trail bikes have been unable to locate Ronald Weaver, last seen in Wahroonga on Sydney's upper north shore about 10am on Tuesday.
"Please, please help to locate Ron," the 79-year-old's wife, Hannah Weaver, said on Thursday.
"He is a good person. Even though he has Alzheimer's, I believe he still deserves quality of life."
An extensive search operation by land and air has stretched into its third day. Police hold grave concerns for Mr Weaver's health and wellbeing because of his medical condition.
Mrs Weaver urged the public to check NSW Police's social media pages to view a picture of her husband and to approach him, saying his name, if he was spotted.
"He remembers his name even though he doesn't remember his date of birth," she said.
The 79-year-old is 159cm tall with grey hair and a bald patch. When last seen, he was wearing a cream t-shirt with a Sapporo beer logo, grey shorts and striped coloured socks.
Police have cast the net wide, with 100 personnel using helicopters, dogs, horses and trail bikes in the search. The NSW State Emergency Service, NSW Rural Fire Service and the National Parks and Wildlife Service have also lent a hand.
Unconfirmed sightings of Mr Weaver place him in the dense bushland and on the fire trail near Cliff Oval in North Wahroonga.
NSW Police Acting Superintendent Carlene Mahoney said time was critical.
"We urge people in the area, in Wahroonga especially, to look through their backyards, look in your sheds, down your driveways," she said on Thursday.
"Hopefully, you might find that Ron has taken shelter (from) the heat over the last couple of days."
