If the answer above is None it means there is no specific mention in the legislation, but you still need to ask local law enforcement before drinking in Australia.
Main article: Alcohol laws of AustraliaAll states restrict purchasing to over 18, but exceptions may apply if accompanied by a parent or guardian. The government-supported Youth Law Australia portal offers details on consumption and supply age limits by state.
You can find more legal details and links here:
Wikipedia Legal Drinking Page