Thank you all for the wonderful comments. It's greatly appreciated.
Originally posted by mroeder75 The good thing: You had a long lens.
The bad thing: You nearly stepped on it anyway.
Yep, It can be handy to have a 500mm lens although the main image was shot at 200mm and the one below at 170mm..
Luckily for this larger snake I was on an elevated timber walkway and it was a couple metres away. I lay down on the walkway to get as low as I could go and bring myself down to its level as much as possible. It was also on a little bit of a mound, up out of the water.
The snake in this next photo is the one that I nearly stepped on. There was a mowed section of grass around part of the wetland. I was standing on the very edge of the short grass trying to get photos of some honeyeaters. I looked down into the taller grass as I was about to step into it to improve my position and only 18 inches from my feet was this fellow. As I didn't have proper shoes on I stayed on the short grass.