Christchurch is the first city in the South Island to receive the new Vodafone 4G network.
The 4G system is capable of uploading data 10 times faster than 3G, and first went live in Auckland two months ago.
Vodafone's head of mobile, Zac Summers, says the company started planning how to improve the network to increase its resilience after the Canterbury earthquakes.
Mr Summers says that involved upgrading its 70 towers to make them 4G capable, and the work is expected to be complete by the end of next month.
He says 70% of the Christchurch population will be able to access the new network.