Vodafone Australia's core network upgrade will make it easier for the company to roll out network expansion plans, CTO Benoit Hanssen has said.

In August last year, the company announced a deal with Ericsson to replace its entire core network with Evolved Packet Core (EPC) and IP Multimedia System (IMS) policy control and circuit switch packet core.

On Tuesday, Vodafone announced that all 4G customers are now on the core network when accessing 4G services.

"It took 10 months to complete the entire IP core swap-out. We did a gradual migration of all of our customers. We started with South Australia and then worked our way through the different customer segments and states, and to complete it all in effect last week," he said.

Hanssen told ZDNet that work is under way to get 3G customers on over the next few weeks.

"3G is still in progress. We're 70 to 80 percent done. There's still a couple of weeks. We're moving customer segment by customer segment over to the core."

Vodafone is undertaking the work at night, when traffic is low, to reduce the risk of outages.

"We do these changes without any customer interruption, but you can never know what might happen. So we do those at night, typically around 1 o'clock at night, but so far the disruption has been minimal or not at all."

Hanssen said that the core network upgrade will help keep costs lower for Vodafone as the company works to expand its network footprint beyond the 96 percent coverage today.

"It's very modern, which gives us all the flexibility we need to upgrade it and increase capacity," he said.

"As you bring in new areas, you only have to make one integration point. There's a lot of secondary benefits that flow through."

Vodafone will receive AU$20 million over the next three years from the federal government to expand its coverage in regional and remote areas of Australia.

At the time of announcing the Ericsson deal, Vodafone said it would use the upgrade to roll out voice over LTE (VoLTE). Currently, a 4G smartphone falls back to 3G to make phone calls, but the company plans to implement VoLTE later this year to make 4G the default for voice calls.

It comes as Vodafone has signed a deal with Stan to offer a subscription to the streaming video-on-demand service. Hanssen said that despite video requiring more data, customers are still using services like Netflix and Stan on the mobile network.

"It's not the majority of our traffic yet, but certainly since these services have come to Australia, there has been an increase," he said.

"We do see a good amount of increase in the over-the-top applications. It's nowhere what you would see on fixed-line networks, but people do watch the remaining five minutes of their episode on the train in the morning or on the metro at night.

"We can't see what type of service it is, but we do see a very pronounced increase in the over-the-top traffic."

The traffic is higher in Sydney and Melbourne, where more public transport is available, he said.