NSW Police confirmed three bodies had been recovered, and an operation was under way to recover the remaining three bodies. There was no further information on the identities of those on board.
There are unconfirmed reports that those on board were four British Nationals, an 11-year-old boy and the pilot.
The aircraft has not yet been recovered, and police said they were unsure whether it would be able to be recovered on Sunday evening.
The Australian Transport Safety Bureau identified the aircraft as a DHC-2 Beaver Seaplane which was "on a return flight to Rose Bay, Sydney Harbour" from Cottage Point Inn.
More about: #Australia