I reckon it's a Red-bellied Black Snake, despite the lack of red colouring on the lower flanks. It was probably in pre-slough phase, when colours are greatly subdued. Did you happen to notice if it had milky eyes? Do you have any other photos of it?
No, did not notice if it had milky eyes. It is very shy & slithers away quickly as soon as it hears the camera shutter. It does seem to emerge late afternoon, presumably to warm up on the rocks before hunting. I will try to get additional photos.
I have just taken additional shots & these clearly show red scales on the belly. The eye looks quite dark and not milky. Is it possible to post another photo to this sighting to confirm? Or I should I create a new sighting?
Thanks for the additional photos Ian. It's definitely a Red-bellied Black Snake. It still may slough soon, as the eyes clear up a day or two before shedding their skin (the eyes are most milky several days before sloughing). One can certainly see the red colouration (albeit dull) better in the addition pics.