can i drive with a cast on my left foot

Short answer: maybe—but only if you can prove you’re in proper control of the car, which is the rule across Australia.

In a manual, your left foot works the clutch, so driving with a cast is a hard no in practice (and a gift to your insurer if things go pear‑shaped).

In an automatic, the left foot isn’t needed, but the cast must not hinder pedal control, vision, or emergency manoeuvres, and you shouldn’t be on impairing pain meds.

Get written clearance from your doctor, notify your insurer, and check your state road authority; if you can’t operate the car safely, you shouldn’t drive—simple.