By all reports, there are some gaps in what is available in the Garmin Australia VFR databases. Truthfully, it doesn't worry me as I have a SkyView system, but in saying that, I wondered if I could narrow those gaps somewhat, given I have made a series of files available that list every Australian ALA and Certified airport for those of us running the Dynon SkyView system.
After a little r search and playing around with Excel today, I think I have manag d to produce similar files for the Garmin crowd, which I've somewhat cheekily uploaded over at the Dynon forums. Hopefully they won't mind too much. So if you have a Garmin G3X system,p and you would like a listing of the airports in Australia as sourced from the May 2018 DAH, nip over to my post at the Dynon forums, and follow the directions. Hopefully the files will work for you.
No promises made either way, good luck!