Returning to your original post in the quest for connectors in Australia. West Marine do carry the connectors for your Washdown Faucets (taps) West Marine washdown Faucet.jpg
If you go to their on line website, check the listing for connectors,you will find (amongst others options) "Seatech's Quick connect plumbing fittings A. Female Swivel Connector, 15mm x 1/2" Nps"
see Seatech's website:-
C L I C K - CONNECTORS
BTW, as mentioned before, American pipe fitting are threaded to the NPT standard - these fittings are Male and Female tapered
. which means the common Australian fittings being straight and without a taper will not screw in more than a couple of threads.
Pipe fittings in Australia are based on the BSP system and metric
since 1988. (Although Australia metricated in the 70's)