Optus has bought more 2100 MHz spectrum in regional areas to complement a similar spectrum purchase in February that bolstered 3G services in capital cities.
The telco said it had acquired a "combination of 10 MHz and 5 MHz of paired spectrum in the 2100 MHz band at almost 1,000 sites across regional Australia".
In February it bought licenses for 10 MHz of paired spectrum in the 2100 MHz band from 3G Investments, a subsidiary of Qualcomm.
Optus said the additional regional spectrum would "significantly increase capacity to existing mobile sites" and support growing demand for 3G voice and data services.
The telco had 3.61 million 3G customers at the end of March, including 907,000 mobile broadband users.
It said customers in Bendigo, Bundaberg, Hervey Bay, Townsville, Tamworth, Wagga Wagga and Port Macquarie would be among those first to benefit from the new spectrum licenses.