Investigation into body found in stairwell

An investigation has been launched to determine why the body an elderly man found in a Sydney shopping centre stairwell lay unnoticed for three weeks.

Bernard Gore, 71, was visiting his family from Tasmania when he left his daughter's Woollahra unit on January 6 to go shopping.

The missing man's decomposing body was discovered in a stairwell accessed via a fire safety door at the Westfield shopping centre in Bondi Junction on Friday.

The centre's owners said "investigations are still underway to determine exactly how these sad and tragic circumstances could have occurred".

One worker told AAP he thought the centre's security was meant to check the stairwell regularly.

Mark Gore said his father was in the early stages of dementia but his condition was helped by medication.

He said Mr Gore had made the journey between his daughter's home and the shopping centre several times previously.

"Unfortunately, we didn't get the result we wanted ... It's just a hard time for us," he told News Corp on Friday.

"We appreciate everyone's efforts."

Police are not treating Mr Gore's death as suspicious but will investigate why his body went unnoticed.