Southwest (Ext): landline numbers and carriers
Southwest (Ext) is one of the town-level numbering areas the ACMA register uses under area code 03 (VIC & TAS). The register lists 26 number blocks for it with about 28,000 allocated numbers, held by 17 carriers. A landline that calls you from one of these blocks was issued for the Southwest (Ext) area — though the line may since have been ported, and caller ID can be spoofed.
Source: ACMA register, data as of 31/08/2026
The carriers in Southwest (Ext)
Southwest (Ext) is spread across carriers: SYMBIO NETWORKS PTY LTD leads with 25% of allocated numbers, and 17 carriers hold blocks in total. The register names the range holder; individual numbers may operate on another network after porting.
| Carrier | Blocks | Numbers | Share |
|---|---|---|---|
| SYMBIO NETWORKS PTY LTD | 7 | 7,000 | 25% |
| PRIMUS TELECOMMUNICATIONS PTY LIMITED | 3 | 3,000 | 10.7% |
| TELSTRA LIMITED | 1 | 3,000 | 10.7% |
| NETSIP PTY LTD | 2 | 2,000 | 7.1% |
| ADARGA PTY LTD | 1 | 1,000 | 3.6% |
| AGILE PTY LTD | 1 | 1,000 | 3.6% |
| C2A INTERNET.COM.AU PTY. LTD. | 1 | 1,000 | 3.6% |
| CHECK TECHNOLOGY GROUP PTY LTD | 1 | 1,000 | 3.6% |
| CHIME COMMUNICATIONS PTY LTD | 1 | 1,000 | 3.6% |
| LMGPS LTD | 1 | 1,000 | 3.6% |
| NETERA PTY LTD | 1 | 1,000 | 3.6% |
| OPTUS NETWORKS PTY LIMITED | 1 | 1,000 | 3.6% |
| PIPE NETWORKS PTY LIMITED | 1 | 1,000 | 3.6% |
| PIVOTEL SATELLITE PTY LIMITED | 1 | 1,000 | 3.6% |
| SOUL PATTINSON TELECOMMUNICATIONS PTY LIMITED | 1 | 1,000 | 3.6% |
Number blocks registered for Southwest (Ext)
The ACMA allocates geographic numbers in blocks tied to this numbering area. Every registered block for this area is allocated to a carrier.
| Block start | Numbers | Held by |
|---|---|---|
| 0361003000… | 1,000 | SYMBIO NETWORKS PTY LTD |
| 0361045000… | 1,000 | OPTUS NETWORKS PTY LIMITED |
| 0361054000… | 1,000 | AGILE PTY LTD |
| 0361183000… | 1,000 | PRIMUS TELECOMMUNICATIONS PTY LIMITED |
| 0361206000… | 1,000 | SYMBIO NETWORKS PTY LTD |
| 0361210000… | 1,000 | SYMBIO NETWORKS PTY LTD |
| 0361268000… | 1,000 | PRIMUS TELECOMMUNICATIONS PTY LIMITED |
| 0361311000… | 1,000 | SYMBIO NETWORKS PTY LTD |
| 0361345000… | 1,000 | PIPE NETWORKS PTY LIMITED |
| 0361380000… | 1,000 | VIRTUTEL PTY LTD |
| 0361409000… | 1,000 | SOUL PATTINSON TELECOMMUNICATIONS PTY LIMITED |
| 0361438000… | 1,000 | NETSIP PTY LTD |
| 0361492000… | 1,000 | ADARGA PTY LTD |
| 0361518000… | 1,000 | THE TRUSTEE FOR READING FAMILY TRUST |
| 0361579000… | 1,000 | NETSIP PTY LTD |
| 0361733000… | 1,000 | SYMBIO NETWORKS PTY LTD |
| 0361734000… | 1,000 | SYMBIO NETWORKS PTY LTD |
| 0361768000… | 1,000 | CHECK TECHNOLOGY GROUP PTY LTD |
Excerpt: the 18 lowest of 26 allocated blocks (source: ACMA register).
Check a number from Southwest (Ext)
Worth knowing
- Block data tells you where a line was issued, not who is calling — and scammers routinely spoof local landline numbers to make a call look nearby.
- Learn more: the Australian area codes guide and how caller ID spoofing works.