She was pleased with the Whanganui numbers but said there was more work to be done.
"If you don't have broadband now, you are completely isolated," Ms Duncan said.
"There's a lot of statistical evidence that shows that people who are able to connect to broadband participate better in things like education and health."
Ms Duncan said the floods last June, which cut off parts of rural Whanganui, highlighted the importance of broadband for assisting rural communities.
"In times of crises, to have communication, to see who needs help, that's absolutely critical."
The total number of national rural connections has grown 73 per cent, according to figures released by Chorus.
The average connection speed for rural New Zealand is currently 13.8 Mbps, an increase of 148 per cent from 5.6 Mbps before the RBI.
Chorus CEO Mark Ratcliffe said people have higher expectations of broadband performance.
"Typically, homes now have several connected devices at any one time, so we are all using far more data and many of us are demanding faster and more reliable broadband speeds to stream or download high definition TV and video," he said.
"The impact on rural businesses and the economy has also started to gain a momentum that can be felt in many communities, with the availability of faster broadband meaning the emergence of new businesses which could never have been contemplated just a few years ago."
Residents who live within about 1km of their cabinet should now be able to access a VDSL broadband service with speeds in excess of 50 Mbps, Mr Ratcliffe said.