I can't help directly as I'm not in Australia..but another alternative is to go to a furniture shop/interior design shop and have some steps custom made for you. That's what I did, I took measurements of the height, width, and depth (of how I wanted each step to be and went to a place here that made custom furniture. (there aren't any for sale here ready-made). Chose the color/fabric and it was ready in a couple weeks.
Good luck!
Good luck!