In principle, individual officers of e.g. CASA and Airservices as well as the entities themselves are exposed to considerable liability, Advance. For example, there was a flurry of ruffled feathers / scared horses when WHS legislation imposed personal liability - including exposure to criminal penalties - on persons "involved in the management" of organisations including CASA and Airservices.
But in relation to e.g. airspace arrangements and the omnishambles that is Airservices and CASA OAR, the exposure is not really from WHS laws. It's more that CASA has powers - lots of powers - to do 'things' about airspace arrangements and an ANSP that CASA has certified, the risks to the safety of air navigation arising from the omnishambles are patently obvious, and CASA appears to be doing nothing. It appears that everyone - including ATSB - is hanging on in quiet desperation, hoping that the roulette wheel is sufficiently large that the number 00 doesn't come up for an RPT aircraft in their life time. If it does come up while the omnishambles persists, the Royal Commission Report and Coronial Inquiry Report and judicial decisions will mostly write themselves.