This below is the Australian Federal Governments Currency Act...

This below is the Australian Federal Governments Currency Act
and below are coins of " legal " tender. They have not called in the 5c as yet, but may eventually.
As for the gold coins?
Cheers
Schedule—Standard compositions of coins

Sections 13 and 14

	Column 1	Column 2
0	Denomination of Coin	Standard Composition
1	Two hundred dollars......................................	11/12ths gold and 1/12th other metal
2	One hundred dollars.......................................	11/12ths gold and 1/12th other metal
3	Fifty dollars.....................................................	11/12ths gold and 1/12th other metal
4	Twenty‑five dollars........................................	11/12ths gold and 1/12th other metal
5	Ten dollars.......................................................	92.5% silver and 7.5% other metal
6	Fifty cents........................................................	Copper and nickel
7	Twenty cents...................................................	Copper and nickel
8	Ten cents..........................................................	Copper and nickel
9	Five cents.........................................................	Copper and nickel
10	Two cents.........................................................	Copper, tin and zinc
11	One cent...........................................................	Copper, tin and zinc