Wallabies are very easily spooked and will bolt, kangas need more encouragement, and only move a certain distance. I would say they are coming for the green grass if your area is dried off.
Look for their poo, that will give you an answer. Wombats do not usually deficate on the ground, more like on sticks or rocks. Roos and wallies leave numerous pebbles, about the size of 20c, or even bigger.
