There are welfare concerns for Thomas 'Eddie' Power, who was last seen at Fiona Stanley Hospital where he was receiving medical treatment.
The 65-year-old resides in North Lake but is known to frequent the Mandurah area.
He is described as 170cm tall with a slim build, green eyes, light brown hair and has several tattoos on both forearms.
Police believe he is travelling on foot and it is not known what clothing he was wearing when he disappeared November 5.
Anyone with information is urged to contact Police on 131 444 and reference IR 131120 1000 16896.