To become a PI you have to get a licence. To get a PI licence you have to have the Certificate 3 in Investigative Services. However, if you do not need a PI licence, but want to be an investigator for government, then you need the Certificate 4 in Government (and its variations).
There are additional requirements to be eligible to apply for a PI licence. These requirements are not the same in all states and territories.
The nationally recognised course is the Certificate 3 in Investigative Services CPP30607 which consists of 15 units of the National Training Package:
You have to complete this course with a Registered Training Organisation. One of the largest and reputable is ASSI which stands for the Australian School of Security and Investigation. We recommend this RTO because we are friends of Adrian Francis, the principal, a man held in highest regard by thousands of former PI students. He is a extensivey qualified and experienced investigator. Adrian is a fantastic trainer who gets top feedback from students all the time. ASSI delivers the course in a combination of online and face to face tuition with lots of real-life and hands-on challenges and practice.
ASSI also conducts specialist surveillance training for private investigators. This is an advanced program for government & commercial investigation professionals. Surveillance training based on current methodologies incorporated by most if not all specialist law enforcement surveillance teams working in Australia.