Mr Norrish has an acquired brain injury and has not been seen since November 25. 

The 52-year-old is described as being about 174 centimetres tall with a slim build, fair complexion, and has a long and pointed brown beard. 

He was last seen wearing cream-coloured cargo-style pants, a dark coloured zip-up jacket, and black Blundstone boots. 

He walks with a pronounced limp.

Mr Norrish’s sister Tammy Williams said her family had made several inquiries in the St Helens area. 

“The locals have been amazing, they’ve all said they’re keeping an eye out,” she said. 

Mr Norrish’s niece Kylie Peake said because of her uncle’s acquired brain injury, every moment of every day is crucial. 

“We are holding onto hope,” she said. 

The family said Mr Norrish was last seen leaving the St Helens tip on his red bicycle. 

Anyone with information about Mr Norrish’s whereabouts should call Tasmania Police on 131 444, or anonymously call Crime Stoppers on 1800 333 000.