Standard AusPost domestic shipping takes between 2 to 6 days, with international deliveries taking around10 to 14 days. Express delivery can be done within as little as 24 hours in Australia, however, times will vary for overseas deliveries.
Although you will get an estimated time of delivery when you purchase Australian Post, this could be subject to change for a number of reasons, such as delays in the delivery line, unforeseen circumstances (such as weather), holidays periods where couriers are particularly stretched or delays at customs (if parcels contain prohibited items or there is outstanding tax which must be paid before a parcel can be released).