2degrees has today turned on its 4G network in central Wellington and more parts of Auckland.
Fourth-generation - or 4G - mobile networks allow users to download or access much larger files such as videos far more quickly than on a 3G equivalent.
The majority of new smartphones, like the iPhone 5 or Samsung Galaxy S5, are 4G-capable.
2degrees, who launched 4G services in the Auckland CBD in June, was later to market with the technology than rivals Vodafone and Spark.
The country's third biggest mobile provider today is turning its 4G network on in over half of Wellington and has extended coverage to more than two-thirds of Auckland.
The North Shore and West Auckland can now access 4G services, the company said.
2degrees plans to launch the service in Christchurch at the end of this month and in Hamilton next month.