Under section 31 of the Road Transport (Driver Licensing) Act 1999 it is an offence to drive whilst unlicensed. To convict you of an offence under this section, police must prove beyond reasonable doubt that you drove on a road or road related area without holding an Australian driver licence.
Penalties

The penalty is determined by whether or not you ever held an Australian driver licence. You will be deemed to have never held an Australian licence if you had not held one within five years of the sentencing date.

The maximum penalty for driving whilst unlicensed is 20 penalty units ($3200). If you have been convicted of driving whilst never been licensed, the maximum penalty is a fine of 20 penalty units ($3200) for a first offence, and a fine of 50 penalty units ($8000) and/or 6 months imprisonment for a second offence. If you are a repeat offender, you will automatically be disqualified from obtaining a licence for 3 years, on top of any other penalty.