also note
"3. It shall be lawful for the Queen, with the advice of the Privy Council, to declare by proclamation that, on and after a day therein appointed, not being later that one year after the passing of this Act, the people of New South Wales, Victoria, South Australia, Queensland, and Tasmania, and also, if Her Majesty is satisfied that the people of Western Australia have agreed thereto, of Western Australia, shall be united in a Federal Commonwealth under the name of the Commonwealth of Australia."
The original set of states were NSW, VIC, SA, QLD and TAS with WA pending at the time of the writing of this constitution. Point 6 that you quoted mentions all commonwealth colonies that can join the commonwealth of Australia as states, "such colonies or territories as may be admitted into or established by the Commonwealth as States". Note that the Northern Terriroy is also named along with New Zealand, though to this day it is still not a state. I believe they had a vote (possibly a few elections ago) on the question of whether or not they wanted to become a state and they voted to remain a terriroty.
Also, New Zealand it self was initially part of New South Wales at one point, though well before federation of Aus
oh yeah, go iTMS for Aus and hopefully NZ.