Telecommunications company Spark is shifting away from the copper telephone network to a fully digital network.
The upgrade will be phased in over the next five years and will bring together all voice communicaitons, including landline, mobile, video or data-based communication.
Spark chief operating officer Mark Beder said the upgrade had been more than a decade in the making as the existing network was near the end of its life and increasingly difficult to maintain.
"Maintaining the network is becoming harder and harder - components are no longer manufactured, we've bought every second-hand part we can source from around the world, and people with the skills to maintain the technology are harder to find."
He said the upgrade was a massive technical and logistical undertaking, but would be largely invisible to customers with minimal disruption to services.
"All the changes take place behind the scenes and disruption to customers has been minimal. The migration entails a small outage of a few minutes, scheduled during off-peak times for residential customers," he said.
Spark said some low-speed legacy services might not be compatible with the new network, such as older EFTPOS terminals and alarms, while new digital services should work better.
The company did not disclose the actual cost of the upgrade, which would be funded from its existing capital expenditure budget.