The sale of wine to anyone who isn't 18 years old or over is prohibited in Australia. By placing an order you confirm that you are at least 18 years old. It is an offence to sell or supply to or to obtain liquor on beHalf of a person under the age of 18 years.
If you are buying a case of wine as a gift - the recipient must also be over 18 years old.
If the wine couriers are in any doubt about the age of the recipient on delivery, they will request some form of ID. If the person receiving the wine is unable to produce appropriate ID, unfortunately the couriers will be unable to leave the wine.