Based on the white gills, possible presence of a ring on the stipe and the stipes thickness, cap shape and scales on the cap this looks like one of the Macrolepiota/Lepiota and related genera group in the family Agaricaceae. My guess would be Macrolepiota but its been >20 yrs since I've looked at these and the more recent molecular data has had some impact on the understanding of the taxonomy of this group. As the photos don't show the base of the fungus it is possible that there is a volva hidden from view which would make it an Amanita.
KenT's suggestion of, and comments about, Macrolepiota are good. Given the more recent studies of Australian specimens, this would now be either a species of Macrolepiota or of Chlorophyllum.