If you're not interested in reading on, the short answer is:
yes, the Australian government can shut down access to the internet
throughout the nation with very little justification, and without
the checks and balances that are required in other developed
nations, such as Canada and the United Kingdom (UK).
Sadly, the recent history of internet shutdowns is something the
mainstream media is loathe to report about.
And the authoritative reasons behind these shutdowns is
something we should all be concerned about.
Internet shutdowns
Internet shutdowns involve disrupting the telecommunications
sector to control the influx and outflux of information in a
specific area. Although we think these may only happen in
third-world countries, the prevalence of information censorship is
a real concern for people worldwide.