The latest Fairfax Media-Nielsen political poll puts National 18 points ahead of Labour.
The survey puts National on 52% support and Labour on 34%.
The Green Party is on 5% support, the only minor party to make the threshold required to enter Parliament.
Support for New Zealand First is unchanged at 3% despite several inquiries into party donations, and the Maori Party is also on 3%.
The Act Party remains at 1% support.
National leader John Key is the preferred Prime Minister for 41% of polled voters, 11 points ahead of the Helen Clark.
The survey questioned 1130 people between 10 September and 16 September, and has a margin of error of plus or minus 3%.
The results excluded voters who had not decided which party to vote for.