2degrees customers with the right phones will be able to make and receive calls over wifi if they find themselves in a mobile blackspot but with access to the internet.



Carrier-based wifi calling has been offered by many mobile phone companies overseas for several years, but 2degrees – which plans to turn on the service "within days" – believes it will be first to launch the service in New Zealand.



One of the benefits is that it allows people to still use their mobiles if they are in a mobile blackspot in their home or office or at a holiday spot with wifi coverage.



The technology can also save people money when travelling overseas.

READ MORE: When is wi-fi calling coming to NZ?

Calls made over wifi in New Zealand will be charged in the same way as if they had been placed through 2degrees' mobile network, chief marketing officer Roy Ong said.

CARL COURT/GETTY IMAGES 2degrees expects wifi calling will be a popular alternative to mobile roaming when customers are travelling overseas.

But if people made a call over wifi while travelling overseas, they would be charged as if they were still in New Zealand.

There would also be no charge for receiving incoming calls over wifi while overseas.

2degrees did not expect it would lose money from that overall, as most customers currently tended to avoid calling altogether when overseas, Ong said.

"Introducing wifi calling to New Zealand represents a genuine innovation in telecommunications that will be of significant benefit to our customers both locally and as they travel internationally," he said.

"We've all had to stand on the picnic table, dash up the hill or seemingly hop on one leg to successfully make a call or send a text from some of our great Kiwi holiday spots. With wifi calling, if you have got wifi you've got 2degrees cell coverage."

There are a variety of third-party apps that let people make cheap or free calls over the internet from their mobiles, such as Skype and Viber, but these require extra steps, such as firing up an app and re-entering contacts.

Ong said 2degrees needed the cooperation of cellphone manufacturers to offer its service, as it required a software update.

2degrees will first offer wifi calling as an option to about 30,000 customers who have Samsung S8 and S8+ handsets. Ong expected it would support a wide-range of mid-range to high-end smartphones by the middle of next year, potentially including iPhones.

Customers would need to select wifi calling as an option on their device. Their phone would then automatically make and receive calls and texts over wifi as the default option if they were logged on to a wifi network.

Ong said calls over wifi would be secure and he expected most customers would simply leave the option enabled, rather than turning wifi calling off and on.