A list of all the capital cites across Australia and there GPO box address and state or territory.
| City | State/Territory | Street Address | GPO Box Address | |
| Sydney | NSW | 2000 | 2001 | |
| Canberra | ACT | 2600 | 2601 | |
| Melbourne | Vic | 3000 | 3001 | |
| Brisbane | Qld | 4000 | 4001 | |
| Adelaide | SA | 5000 | 5001 | |
| Perth | WA | 6000 | 6837—6848 | |
| Hobart | Tas | 7000 | 7001 | |
| Darwin | NT | 0800 | 0801 |