Police said Brian Anderson, 29, was last seen in the area on July 8, 2021.
He is described as 5ft 10in with an average build. He has very long black hair with a beard and normally wears a red bandana, jeans with holes in them, with red and black trainers.
He is thought to be with his dog, a white and brown American Pitbull/Bulldog. Police said the dog has been taught to attack and may be vicious.
A police spokesman said: “Please do not approach if seen, but instead contact us on 101 quoting ‘Operational Colonel’.”