What makes you think it doesn't? They're clearly allowed to:
Airspace Regulations 2007
6 Designation of prohibited, restricted or danger areas
(3) CASA must not declare an area to be a restricted area unless, in the opinion of
CASA, it is necessary to restrict the flight of aircraft over the area to aircraft
flown in accordance with specified conditions in the interests of any of the
following:
(a) public safety, including the safety of aircraft in flight;
(b) the protection of the environment;
(c) security.
https://www.legislation.gov.au/Details/F2016C00341