Winston Peters' party increased its vote more than any other on Saturday, jumping to 8.85 per cent from 6.59 per cent in 2011.
It performed best in its traditional strongholds in the Bay of Plenty, Whangarei and Northland, where it polled close to 15 per cent.
Many expected that the Conservative Party would be the greatest rival for New Zealand First's vote.
Mr Peters regularly attacked the Colin Craig-led party, accusing him of stealing New Zealand First's policies and telling the public that a vote for the Conservative Party was a wasted one.
However, both Conservatives and New Zealand First increased their share of the party vote in Saturday's general election as New Zealand voters shifted their allegiance further to the right of the spectrum.
New Zealand First appeared to gain most of its new votes from ex-Labour voters, especially in rural areas and in the Bay of Plenty.
In a number of electorates a 2 or 3-point drop in support for Labour coincided with a similar increase for New Zealand First.
Mr Peters' campaign strategy was to focus solely on the party vote.
New Zealand First once held all of the Maori seats and it continued to perform well in these electorates, winning an average of 13.3 per cent. This gave it a significant advantage over centre-right rival the Conservative Party which got just 781 votes.
Mr Peters' party performed worst in urban centres such as Epsom and Mount Albert.
The New Zealand First leader has unsettled some in the Asian community with his hard line on immigration and foreign ownership, and these seats have a high proportion of Asian residents.
Nearly one in three residents in Epsom identify as Asian, and nearly one in four in Mt Albert were of Asian descent.
- By Isaac Davison of the New Zealand Herald
