National's lead over Labour has increased to 11 points in the latest Roy Morgan poll, in contrast to the research company's survey two weeks ago that had the lead narrowing to three points.
National's support rose to 43% in the poll released on Friday, while Labour's support fell to 32%.
However the Green Party, which has said it would prefer to work with Labour post-election, has recorded its best ever result in this poll, of 11% support.
New Zealand First scored 4.5 percent, just below the 5% threshold needed to stay in Parliament.
ACT was unchanged on 3.5% while other parties barely registered.
The poll of 743 voters was taken between 6 October and 19 October, has a margin of error of plus or minus 4%.
Other polls taken around the same time have returned different results, but all have National ahead of Labour.
A Herald-DigiPoll published on Friday 24 October showed the Labour Party making a small gain, but National still about 13 points ahead.
The survey put Labour up 1.3% to 37% and National down 1% to 50.4%.
The Greens moved up a small margin to 5.4%, and the Maori Party was also slightly up, at 2.4%.
New Zealand First fell to 2.1% support, while ACT was at 1.2 %.
The survey of 750 respondents was carried out between 15 October and 22 October and has a margin of error of plus or minus 3.6%.
Maori party 'kingmaker'
However, in a poll released by TV3 on Thursday 23 October had a Labour-Green coalition neck-and-neck with National and ACT.
In the 3 News poll Labour was down one point at 37.4%, while National remained steady on 45.1%.
But the Green Party polled 8.8% support, while ACT was on 1.7%, meaning the Maori Party could determine which party leads the Government.
The Green Party has said it would prefer to work with Labour after the election.
New Zealand First support rose to to 3.5%, the Maori Party was on 2.3%, and neither the Progressives nor United Future reached 1%.
The survey of 1,000 eligible voters was carried out from 16 October to 22 October and has a margin of error of plus or minus 3.2%.