Telecommunciations company 2degrees has started the first steps towards a 5G mobile network.
It will roll out the service initially in Auckland and Wellington this year, and progressively extend it to about 700 sites around the country.
2degrees chief executive Mark Aue said the company has been able to take advantage of the latest technical developments in 5G technology.
"Our launch will be well timed and what we're building today will be far more advanced than what any telco could deliver a year ago."
Swedish telecoms provider Ericsson will provide the technology, after the equipment provider for 2Degrees' earlier generation networks - Chinese-owned Huawei - was banned by the government from involvement in 5G networks on security grounds.
"Ericsson is rapidly expanding its New Zealand presence and we look forward to bringing our customers the technology that is underpinning the world's best 5G networks across five continents, including Australia's leading mobile network," Aue said.
"What we're building today will be far more advanced than what any telco could deliver a year ago. In the past 18 months there have been significant advances in the 5G ecosystem and our 5G build is poised to capitalise on that."
He said as it rolled out the new network it would also double the capacity of its 4G network.
Rivals Vodafone and Spark already offer 5G mobile services in parts of the country.
5G mobile networks offer high speed connections to a wide range of devices and allow the transfer of large amounts of data, which would cut out the use of fibre and cable fixed connections.
Last year the government made a temporary allocation of the necessary radio spectrum to allow 5G services, but has yet to decide when it will hold an auction of the spectrum.
Aue said the upgrading and expansion was being funded from its established capital investment plan.
2degrees' shareholders are looking at a possible share float and stock exchange listing.