Improved 4G services will be available in Belconnen, Woden, Tuggeranong, Civic, Crace, Mitchell, Watson and Curtin, and more sites are expected to be switched on before Christmas.

The boost to 4G coverage comes after Optus received early access commercial licence approval for 700MHz spectrum from the Australian Communications and Media Authority.

The 700MHz spectrum was previously used for analogue TV broadcasts, but from January 2015 it becomes available nationally for commercial use by telcos.

Currently, Optus 4G services in Canberra have only been provided by the 2300MHz spectrum.

Optus managing director of networks Vic McClelland said the 700MHz spectrum brought 4G coverage to more places and improved indoor data access.

The expansion is part of a nationwide roll-out of 4G 700 MHz services.

Canberra joins Darwin and Perth as the latest capital city to benefit from the stronger Optus 4G network.

Telstra is yet to switch on its 700MHz spectrum 4G services in Canberra.

A Telstra spokeswoman said the introduction of the 4GX service in the capital was planned for January 2.

"Telstra's 4G services in Canberra have already been boosted through the introduction of services over the 2600 MHz spectrum," he said.

"The introduction of 4GX services ... will bring even higher speeds and extra 4G coverage."