A lack of family is making the search for missing Dunedin man Gordon Mclean more difficult for Police.

The 63-year-old, who has dementia, left Wakari Hospital at around 3PM Thursday.

Search and Rescue co-ordinator Sergeant Richard Panting said not having any close family members is making it hard to create a profile for Mr Mclean.

"We'll normally interview family members and friends and build up a profile of what a subject would like to do, or not like to do and as a result will direct some of our tasks based on that."

1600 hours of volunteer time has gone in to the search but to no avail.

Panting said Mr Mclean is frail, standing at 152 centimetres tall, and only weighing 48-kilograms.

"He hadn't eaten in the days preceding going missing so as a result it increases the risk for him."

Anyone with CCTV cameras in the area are asked to hand over footage to Police.