Our contract with Australia Post is for signature required on delivery but this can be changed at your discretion in the Australia Post 'MyPost' app, as can the delivery address.
When you receive your tracking email simply click on the tracking link. If the order has been collected by Australia Post this link will be active. You can then change or correct the delivery address as well as change the delivery to ATL which is the authority to leave the delivery with a signature being required.
If the Australia Post contractor assesses that it is not safe to leave a delivery, even with an ATL, they can card it to a Post Office for the security of the delivery. Amongst other factors that may influence this, Australia Post does monitor parcel thefts and warns contactors of trouble hot-spots.