All "hot" sauce possess a certain amount of heat, but it can be hard to know exactly how much fire you're going to get before tasting. The below chart from Sriracha2Go, which ranks sauces by Scovilles, can give you a glimmer of what you're getting into.
Photo by Ben Grey.
It doesn't contain every hot sauce you'll encounter in the wild - and some are only available in the US - but it does give you an idea of where some of the super popular ones fall on the Scoville scale. This can be helpful if you're particularly sensitive to heat (or like your sauce to pack a punch).
At least five of these are readily available at Australian supermarkets. The others might require a trip to a speciality store or some googling. Make it hot!