"'Our network traffic monitoring is showing that there are homes and businesses on fibre 100/20Mbps who regularly max out their broadband connection.
"While applications manage this congestion, it can result in buffering or lower resolution streams that can detract from the enjoyment of a great broadband experience.
"The performance upgrade we're announcing is a significant step forward, tripling the download speed of our most popular fibre plan."
NOW Broadband chief executive Hamish White said the increase in speeds was coming at a good time.
He said New Zealand was experiencing record demand on internet traffic, compounded by lockdowns.
White said New Zealanders consumed 26 petabytes of data in a single day last month which was the equivalent of a Netflix HD stream running for 1000 years.
However, he said there was potential for some service providers to charge customers extra for the increased speed, despite Chorus not increasing the price.