We live in Victoria. A friend's GP handed this to him before prescribing CBD oil:
"Can you drive after taking CBD oil in Australia?
Yes, as long as you do not have any THC in your system. If you are prescribed a CBD only product then you may legally drive. If you take a medication containing THC and test positive for THC in a mouth swab test, you can lose your license.
Patients taking cannabidiol-only medicines can lawfully
drive, as long as they are not impaired. Drivers should check whether the medicinal
cannabis product they have been prescribed contains THC. Many medicinal
cannabis products do not contain THC".
He was also referred to the following VicRoads website:
https://www.vicroads.vic.gov.au/safety-and-road-rules/driver-safety/drugs-and-alcohol/medicinal-cannabis-and-driving
For him and his family it was decided he would not take the risk of being tested and failing.
Hope that helps.