It has been three weeks since Mr Bernard's dismembered body parts were first found floating in the river near Oakland Street in Moonee Ponds.

However, some of his body parts remain missing.

Police will return to the scene in the hope of recovering all of Mr Bernard's remains.

Divers will focus their efforts near Burton Crescent, Maribyrnong.

Mr Bernard's remains were identified after police released an image of a distinctive tattoo of a devil holding a pitchfork and a spray can inked on his forearm, which was found in the river on February 5.

"Investigators would like to reassure local residents that the police activity today is an extension of the previous search activity, as all the remains have not been found," Acting Sergeant Julie-Anne Newman said.

Police have not confirmed media reports that Mr Bernard may have been killed over outstanding drug debts.

It has been reported that up to three men and possibly a woman are of interest to homicide detectives.

Mr Bernard, 32, was the eldest of four children and described by police as having been a couch-surfing "itinerant", who stayed with different friends.

He lived in North Melbourne and frequented the Fitzroy area, but it is unclear whether he was in contact with his two Melbourne-based siblings.

He was last seen in the CBD on the afternoon of Tuesday, January 27.

Anyone with information about Mr Bernard's death, or his final movements is asked to contact Crime Stoppers on 1800 333 000.