From Wiki

The Australian currency is the dollar (symbol $, also sometimes written AUD, AUD$, A$). One dollar can be divided up into 100 cents.

[edit] Bank Notes

There are 5 Australian bank notes, with values of $5, $10, $20, $50, $100.

See: Reserve Bank of Australia's Notes in circulation, with photographs.

[edit] Coins

The coins in circulation are, 5c, 10c, 20c, 50c, $1, $2

When dealing with cash, there are no 1c coins, so transactions are rounded up or down to the nearest 5c. Electronic transfers are not rounded.