As video streaming services surge in popularity, Kiwis are consuming far more internet data than ever before.
Spark said the average New Zealand house now used about as much data in a year as the whole country used each month in the late 1990s.
Rival telecom company Vodafone said video streaming now made up 60 per cent of its home broadband traffic.
On-demand streaming services such as Netflix and Lightbox drove much of the surge, the companies said.
Spark said average monthly data use per household for its broadband customers had grown an "incredible" 29 per cent in just three months.
New Zealand was now witnessing a "video streaming revolution" which had changed how Kiwis used the internet, said Chris Quin, Spark's chief executive for home, business and mobile.
"It's hard to think of any other industry that is experiencing such levels of growth."
He said the increased data use was evidence of a major "lifestyle and behavioural shift" as more people bought into higher data or unlimited broadband plans, and enjoyed online entertainment on their own terms.
The huge appetite for data meant congestion on the data superhighway was growing.
Spark said that as more people used more devices and gobbled up data from TV streaming services, it would work with partners such as infrastructure company Chorus to ensure prodigious consumption didn't outstrip infrastructure.
Lightbox chief executive Kym Niblock agreed that the rise of video streaming services was changing how Kiwis used the internet.
She said peak bandwidth that Lightbox delivered had increased by over 400 per cent since the year started.
In February, the average Spark customer used 42.5GB. Last month, they used 55GB. Vodafone said its customers last month used an average of 58GB of fixed broadband data per household.
Its consumer director Matt Williams said the company expected its internet traffic volumes to grow by 85 per cent annually. Customers were drawn to unlimited broadband plans and the Netflix and NEON streaming video service, he said.