Pygmy Mole Crickets could easily be overlooked. These are only about 3 mm in length! They are strong jumpers and can leap a metre or so with a single hop. :Pygmy Mole Crickets are members of the family Tridactylidae.
A number of species are known from Australia and are placed in two different subfamiles. I covered these in the book below. The crickets, not really "crickets" in the true sense, live in short burrows they make in wet ground. They are said to feed on algae that the scrape from pebbles.
Note the very short wings. This is a flightless species. It was originally thought that these insects were related to Mole Crickets (Gryllotalpidae) but they were found to be examples of convergent evolution. John & Rentz (1987) showed that they are properly placed in the Caelifera, and as such they are phylogenetically closer to grasshoppers than they were to Mole Crickets.
John, B., Rentz, DCF. 1987 The chromosomes of four endemic Australian fossorial orthopterans: A study in convergence and homology. Bulletin of the Sugadaira Montane Research Center. 8: 205-216.
Rentz, DCF. 1996. Grasshopper Country: The abundant orthopteroid insects of Australia. University of New South Wales Press. Pp. 1-284.