This is beautiful. Looks alot like Vanessa cardui but V. cardui doesn't have the blue eyespots on the hindwings.
I wonder what the caterpillars look like? I'll have to look into that. But this is what Wikipedia has to say:
Vanessa kershawi, commonly known as the Australian Painted Lady, is a butterfly that is mostly confined to Australia, although westerly winds have dispersed it to islands east of Australia, including New Zealand.
During spring adult butterflies migrate south in large numbers from northern states of Queensland and New South Wales. In 1889, this migration was so large that trains were unable to generate sufficient traction because of the large numbers of butterflies resting on the tracks.
A major food plant is Ammobium alatum.
The rest of the info can be found here. Funny how all Vanessa sp. used to be under the genius name Cynthia and how both of these names are names of people.
I wonder how that came about? That's something else to look into. But for later.