When your say ERSA data, what do you mean exactly ??
If your looking for waypoint, navaid, airway data (because you've mentioned AsA's enroute charts) then AIP/DAH data is what your after !!
To answer your question, yes, the data is available but not from AsA.
There are a number of third party aeronautical data providers (as mentioned earlier Jeppesen is one provider) that subscribe to Aust AIP's then manually convert/code to an electronic (ARINC 424) format for FMS, flightplanning and GIS systems.
How much are you willing to pay fo it ????.........I could be convinced to help you out.....