The Transport Security Regs require a holder of a Flight Crew Licence to have a current security check ie ASIC or AVID.
RAAus etc are not licences, they are certificates issued by a non government entity.
Holders of those only need them if they are going to an aerodrome that requires ASICs to be airside.
It is ridiculous and this has been pointed out to the OTS before.
Just bear in mind that in some parts of the world you need the equivalent of an ASIC for every different aerodrome you fly into, so having one for the whole country makes more sense than that.