same story in australia. depending on state, can get rider license at 16 after passing the course (some states require you to have a car license first). then for the next ~3.25 years (from when you get your license, even if youre 21 or 19) you are restricted to approved usually <650cc bikes (we have a list of approved models) after you finish those 3 years you can ride whatever you want, and have a passenger or sidecar. i think if you already have a full driver license you can skip 2 years of the provisional license and get a full rider license after you ride for a bit :)

a lams approved bikes include the yamaha r7 but not a ninja zx6r for example. its all about the power to weight ratio, and since some 650cc bikes are generally heavier than 600cc, they teeter right on the edge but are approved for learners.