It was thought to have died out on the Australian mainland more than 50 years ago, but the confirmed discovery of an eastern quoll has raised hopes the animal might yet be surviving in NSW.

The spotted, carnivorous marsupial weighing about a kilogram was once common in south-eastern Australia but disappeared after the introduction of red foxes.

Though there are still eastern quolls in Tasmania, the last mainland specimen came from Nielsen Park, in the exclusive eastern Sydney suburb of Vaucluse, in 1963.

Another eastern quoll has now been found.