I thought this this was a reasonable assessment of the status:
Assessment of Evidence of 'Big Cats' - Department of Primary Industries
Hawksbury City Council have been trying to get the NSW state government to look into reported sightings to determine one way or the other if they exist. There is a group operating in that area that have been monitoring and documenting sightings. A vet has also been involved and supports the theory that they do exist.
The group have sent samples of scats found in the bush to be analysed by the recommended government laboratory - they reported the scats were from a canine and the fur in the scat determined to be cat fur from cats eaten as prey. A control sample from a leopard in a private zoo that included fur from self grooming was also sent - the resulting analysis was the same. Perhaps their tests were not geared up to determine the difference between canine and and feline scats let alone the difference between domestic cat and exotic cat?? Or... maybe there is a cover up?
There's lots of info out there.
Who knows either way? Can't say they do, can't say they don't.

