Family never reported disappearance of dead Sydney dad

Investigations will continue into the death of a northwest Sydney man, whose family never reported his disappearance to police.

Two members of the public spotted the body of Michael Gavanas, 50, in mangroves on the banks of Parramatta River at Melrose Park around lunchtime on Saturday.

So far, police are not sure how or even where the Westmead man died but they have formed Strike Force Cambronne to investigate what is being considered a suspicious death.

Ryde Local Area Command Superintendent John Duncan would not comment on whether Mr Gavanas had any underworld or mafia links.

"At this point in time we're pursuing several lines of inquiry, and I don't wish to disclose those at this point in time for operational reasons," he told reporters on Monday.

Mr Gavanas, who was known to police, was married and had three adult children.

He also had a young daughter who still lives at home.

Asked about the Gavanas family's failure to call police, Det Supt Duncan said: "Look, every family's different. But at this point in time the family are working with police."