As far as I know Australian universities do allow retakes but your failures will greatly affect your overall CGPA.

Each failed subject will add on to your existing number of subjects with a very low score of 1.0.

Meaning if you failed 1 subject and your course has 20 modules, your CGPA will be calculated as 21 subjects with a very low 1.0 point added as a penalty and divided by 21 subjects.