There's been no announcement from Amazon, but the Australian Kindle Store is now live and it is selling ebooks. It currently lists 2.1 million titles in stock as well as the Kindle Paperwhite, basic Kindle,and the Kindle Fire HD and HDX. Prices start at $109 AUD.
I'm sure this is going to please Australians, but more importantly (from the viewpoint of Amazon) this should also stop their market share from dropping.
While Amazon has been selling ebooks in Australia since 2009, they have been making their Australian customers buy from Amazon.com and pay in in US dollars. Naturally that has led to a fair amount of friction as customers balk at the idea of paying in a foreign currency and buying from a company that pays no taxes, isn't creating any local jobs, and gives no specific support to Australian authors and publishers.
I have been told that these complaints are part of the reason Amazon's share of the Australian ebook market has shrunk to an estimated 65%. I don't know if that is true, but it would make sense.
On the other hand, Amazon has been facing fierce competition in Australia from Google, Apple, and Kobo, all of which have a local presence in Australia. There are also a number of independent ebookstores in Australia, including some powered by txtr and by OverDrive.
P.S. And in case anyone in new Zealand is wondering, the site Amazon.co.nz still redirects to Amazon UK.