Bernard Gore, from the Hobart area, vanished on Friday.

He is in Sydney visiting his daughter.

NSW Police said Mr Gore was last seen leaving a unit block on Ocean Street, at Woollahra, about 12.30pm to go shopping at Bondi Junction.

He was expected to meet family there, but didn’t.

Police are concerned for his welfare due to his age and the extreme heat in Sydney in recent days.

Mr Gore’s son, Mark, has travelled from Hobart to join the search.

He said his parents had been staying with his sister and her family in Woollahra since December 15, and Mr Gore had made the journey between their home and the shopping centre several times without a problem.

“My father would not want to be a bother to anyone if he was lost, and I think it’s unlikely he’d approach a stranger for help,” Mark said.

“I hope someone will notice him alone and ask if he needed help; he’d probably say he was fine but people need to contact police if they think it is him.”

Mark said his father was only in the early stages of dementia, and this was helped by medication; however, he’s now been without his medication for four days.

“We are overwhelmed by the situation and worry he might have got onto a bus or a train and could be anywhere,” Mark said.

Bernard Gore is described as being of Caucasian appearance, about 180cm tall with a slim build, with grey/balding hair, clean shaven and may respond to the name ‘Butch’.

He was last seen wearing a grey turtle-neck skivvy underneath a black-and-red checkered flannelette shirt, grey trousers with two black stripes down the legs, white sneakers and a cream Panama-style hat with a black ribbon.

Police received an unconfirmed sighting of Mr Gore in the East Hills Park area on Friday afternoon.

Anyone who has any information on Mr Gore’s whereabouts is urged to contact Crime Stoppers immediately on 1800 333 000.