Charles,
The AS 1210 is not mandatory for offshore installation, unless is mandated by the customer specification. I assume the question was rather the vessel has to be registered with the Australian authority or not. The answer;- the registration is not mandatory for the offshore platforms. However, the registration may be mandated by the insurance company, who need assurance of equipment safety. One way could be the U-stamp, another way to register it voluntarily with the local government (WA waters, QLD waters, etc.). That way the design verification, manufacturing inspection is completed by means of U-stamp or registration with Australian local government, to the satisfaction of the insurance company and the user. Depending on the equipment and the manufacturer, the U-stamp might not be feasible, but the registration is equivalent assurance of quality, without the U-stamp expenses.
Cheers,
gr2vessels