Chorus' data spiked to its highest ever use last week after tens of thousands of people downloaded a popular game.
A boy plays Fortnite. Photo: AFP
Chorus network strategy manager Kurt Rodgers said the spike was "unprecedented".
"We have never seen a spike of this magnitude on our network before."
Data use grew throughout the day, peaking about 9pm when "hordes of people" streamed online video.
On Thursday, the peak was about 20 percent higher than normal and coincided with the video game Fortnite version five being available for download.
The peak was the equivalent of about 30,000 gamers downloading the game's patch, Rodgers said.
"We manage capacity to keep the network congestion free. It's like being able to add another lane to a motorway before it starts to congest.
"Gamers can play away while others in the house can stream TV, video chat, work, play or do their banking with nobody slowing down."