The Certificate I course is aimed at the basic skills and knowledge leading to an Australian Security licence.
For example: the following unit is a level I unit and needs to be studied if you wish to be a security guard in a licensed premises that sells alcohol:

The Certificate II in Security Operations course has most of the basic units required for the issue of an Australian Security licence, but you need to choose the electives that will give you the licence you want in your state. If you want to work as a security guard or security officer, most likely, you will need to have the Certificate II in Security Operations.

Each state of Australia has a different number and list of units required to be studied for the issue of security licences.

LICENCES: General Guard, Crowd Control, Body Guard, Monitoring Room and Firearms/Armed Guard

This course is mainly used by current security officers wanting to study more advanced, specialised skills like crowd control, body-guarding, monitoring room operations etc who are wanting to make security their career.
For example: the following two units need to be studied if you wish to be a Crowd Controller.

This security certificate course is the pathway for a career in security and risk management, for guards wanting to not only work in security operations, but move into the area of managing risk.

This Diploma security course is for experienced security officers who have a breadth of skills and knowledge of coordinating security operations, managing security officers and who have some experience in managing risk.