24/7 Parcel Lockers at some Post-Offices, for those without postboxes. With these the customer uses a code sent by Australia Post to open the locker.
For home use, there are some designs of locker which can be installed at the front fence or door. These are registered online and provide a way for couriers to access the customer's locker and indicate the item has been delivered. The My Parcel Box Vault requires the payment of a weekly service fee, whereas the Pakman Parcel Delivery Box is a one-off purchase. The Packman has a chute, which allows packets to be delivered, but not removed. There is also a combination locked door for large boxes (wine case size). Also there is a barcode on the box for the courier to verify delivery.
The Packman looks well thought out: it comes in colours which will blend in with most homes (white, sand and grey) and while larger than a normal mailbox (525 x 905 x 420 mm), it would not look out of place next to a gate or beside the front door (it can be free-standing or built in). There is an optional ordinary mailbox to go on top of the unit. At $428 with the optional mailbox, this is more expensive than the average pillar letterbox, but you are getting a much bigger box for your money,
But there are some limitations with the Packman: The unit appears to be built from steel, with no insulation, so it could get very hot in the sun (particularly the grey coloured unit). So while it is large enough to fit a case of wine, you may not want this, or other drinks or food, delivered. This may be less of a problem if you have the unit built into a brick fence or the front of the house.
The next problem is that the parcel door seems to be unsecured. This would allow trouble makers to insert rubbish, liquids, or firecrackers in the slot. But it would not be difficult to disable the chute, so the combination code is required for all deliveries. However, this exposes another problem: there is only one combination. The delivery person requires the combination to open the door to place a large item in the locker. They can then remove what is already in there. It is possible to resent the lock to a new combination, but this is a mechanical lock, requiring a fiddly process, involving a paper-clip. You then have to register the new combination on-line for subsequent deliveries. An electronic combination lock, with a different code for each delivery would be more secure, but much more expensive and complex to install.
This raises an interesting issue for apartments, where the mailboxes are clustered at the front door. There may not be enough space to install a large parcel-box for each unit. Perhaps smaller units could be provided, or a system like the Belconnen Westfield mailboxes. A set of non-dedicated parcel-boxes would be provided. The courier would place the delivery in a box and then inform the customer it is read for collection. After the customer clears the box it would be available for other deliveries. This could use physical keys, or electronic codes.