I have used a Garmin E-Trex for years and last year switched to a Garmin Rhino 650. It is fantastic, comes with a map of Australia which is all you will need. It shows the smallest creeks and tracks when you zoom it in. Also has a 5 Watt UHF, you can send text messages to other Rhino users and if there are several people hunting in group and every one has one than you can see where the other people are on the map. Many other usable features as well. They are not cheap but well worth the money.

Waidmannsheil.