The electrical current in Australia is 240/250 volts AC, 50 cycles. The Australian three pin plug is extremely safe. Adaptors are usually required for most foreign appliances. A transformer may be required if you bring an appliance from overseas that operates on a different voltage.
Electrical sockets (outlets) in the Commonwealth of Australia are the "Type I" Australian AS-3112 type. If your appliance's plug doesn't match the shape of these sockets, you will need a travel plug adapter in order to plug in. Travel plug adapters simply change the shape of your appliance's plug to match whatever type of socket you need to plug into. (Note: The Australian standard is very similar to the Chinese CPCS-CCC and Argentine IRAM sockets. Although the three standards are technically different, they are practically interchangeable, and are all grouped together under the general, unofficial "Type I" classification. The same adapter can be used in sockets of all three standards.)