John Bennett, also known as “Stoj” was last seen near Westfield Bondi Junction on June 2.
His sister, Desley Weier, said her 47-year-old brother’s disappearance was “completely out of character”.
Mr Bennett left his Bondi Rd, Bondi Beach home taking just his keys and mobile phone.
“He has never done anything like this before. Police have done bank checks and hospital checks, but we have heard nothing since,” Ms Weier said.
“He has not used his phone, there has been no use on that phone since June 1 — whether he has lost it or just run out of credit.”
She said family and friends had put posters at Bondi, Bronte and Maroubra beaches in hope somebody could shed light on his whereabouts.
“We had a call from his friend who saw him on May 31st and said he was in good spirits,” Ms Weier said.
“We just want to know that he is OK and safe and please call us if you’re out there.
“We are worried, we miss you.”
Mr Bennett was well-known in the Bondi community and was last seen pawning an item at Cash Converters Bondi Junction.
He is described as caucasian, with a slim muscular build, about 170-180cm tall, 65-75kg, clean shaven with short black hair.
Anyone with information should call Waverley Police 9369 9899 or Crime Stoppers on 1800 333 000.