If a drone weighs more than 2kg, you will need to be licensed and/or certified to fly.
If you want to fly outside these operating conditions, you will need to be licensed (hold a remote pilot's licence RePL) and fly with a certified operator to fly commercially.
If you violate these rules, CASA can take action against you in the form of fines of up to $8500 per offence. If you put people at risk or seriously injure someone, the penalties are far more serious and will be dealt with on a case by case basis.
For more information on using drones over 2Kgs can be found on the CASA website.