In every Australian state, including Victoria, fixed electrical wiring work must legally be carried out by a licensed electrician. This includes power points, light switches, light fittings and anything connected to your home's fixed wiring.
Fixed wiring work carries real risk of electric shock and fire if done incorrectly, and mistakes aren't always visible until something fails. Licensing exists to make sure the person doing the work understands wiring rules, earthing, circuit loading and safe isolation.
Plug-in items like lamps, appliances, and anything that connects via a standard plug are fine to handle yourself. Replacing a light globe is also fine.
Aside from the safety risk, unlicensed electrical work can void insurance, create issues at property sale, and won't come with a compliance certificate, meaning there's no record it was done safely.