Ann meant that there is a lot of chemistry B&H won't ship anywhere, including the U.S. Rodinal (Adonal) is an example. They seem to be unique in this. Freestyle would be a possible alternative. Presumably they would be aware of any shipping restrictions to Australia, and should be able to assist.
No restrictions on importation if you are a commercial lab with import clearances and Customs formalities in place, but for any other purpose (amateur or home darkroom use) you will be out on a limb. Vanbar in Melbourne / Camperdown NSW is worth trying for chemicals before handing over to the USA.
There are no real cost savings to be achieved by shopping by post at B&H from Australia.