The increase is driven by surging demand for streaming services such as Netflix, statistics from Chorus show.
Chorus market insight head Rosalie Nelson said the average Dunedin home used 47GB of broadband data in January 2015 and 109GB in June 2016 - a 130% increase.
She said Dunedin's Gigatown status meant connection speeds had also increased by 255%, reaching an average of 151Mbps in 2016, compared to 43Mbps last year.
Broadband consumption in the Clutha, Central Otago, Queenstown Lakes and Waitaki districts has also more than doubled in the past 18 months.
The average Clutha district home usage increased from 28GB of broadband data in January 2015, to 58GB in June 2016, and speeds increased by 30%.
During the same time frame, the average Central Otago district home usage rose from 29GB to 55GB - a 91% increase.
In the Queenstown Lakes district, usage rose from 45GB to 91GB (a 102% increase), with connections speeds increasing by 64%.
Use in Waitaki homes rose from 28GB in January 2015 to 67GB in June 2016, an increase of 137%. Connection speeds also increased by 79%.
Nationally, the average New Zealand home used about 102GB of broadband data in June 2016 - more than double the 49GB used at the start of 2015.
Ms Nelson said the figures showed faster broadband was now, more than ever, an essential part of many New Zealanders' daily lives.
``More than half of New Zealanders now watch internet TV where the number of online film and TV platforms has exploded.
``But this isn't just about watching more and more content online, it's also about the rapid digitisation of our everyday lives.
``Broadband as the fourth utility, sits at the heart of the home and plays a pivotal role in how we function in our day-to-day lives.''
Ms Nelson said homes now typically had several connected devices at any one time, and with this surge in data use, people expected and demanded faster and more reliable broadband speeds.
Ms Nelson said New Zealand had already seen dramatic improvements in broadband thanks to the Ultra-Fast Broadband and the Rural Broadband programmes.
``Right now, more than 700,000 New Zealanders - that's the combined population of Dunedin, Christchurch and Hamilton - can access faster broadband than they currently have.''
Ms Nelson said with the way broadband data was used now, broadband plans with data caps were no longer practical.
``More and more consumers want the freedom of unlimited plans.''
