According to the Royal Central blog:
Four years ago, during the Commonwealth Heads of Government meeting in Australia, an agreement was made between those 16 countries…that there would be changes to the royal succession laws.
Ironically, the hold-up for these changes is down the very state from which they originated in Australia.
…the Western Australia parliament has not yet passed the changes. As part of arrangements in Australia to recognise the autonomy of its state parliaments, the Western Australia Parliament must also first pass the necessary laws before the final seal can be given by the Federal Parliament of Australia.
To read the entire article on the Royal Central blog, please click here.