Just a bit of background info and after all the years my facts may be a bit out. As I remember it the first comms or at least some of the first out of Darwin may have been from the RAAF control tower in Darwin to RAAF Base Ops in Canberra by phone. That was all that could be established at that point very early on. Base Ops in Canberra was right next to the old "civil" Approach Control Unit. The Approach Control unit Flight Data officer (civil not RAAF Controller) then became the link between Darwin and the National Disaster Centre being set up in Canberra to coordinate the evacuation etc etc Eventually the Flight Data Officers ended up completing quite a few shifts in that centre in Northbourne Ave in Canberra. They basically assisted the fairly complicated comms between Darwin and the various emergency services. I do remember a "Bushies" DC3 being in the fray somewhere and perhaps positioning up from Alice Springs. I later found out a mate of mine was crewing it.
The comms that were established by "just trying it" were quite amazing. Years prior to the internet I thought it would be worth a go to try out the "addressees" of the police teleprinter system into the departure messages from Darwin (RAAF ATC) via the aviation or "AFTN" printer network system. There was no connection as far as anyone knew but it worked. The police in NSW was one example where if I remember correctly, they got the departure messages and others directly but then couldn't understand many of them.
An attempt at keeping an accurate log was made, from memory although all was quite chaotic, and could possibly be obtained if archived in Canberra somewhere wherever the National Disaster Centre records are archived.