The latest Taxpayers' Union-Curia poll has National on 34.9%, down 4.1 points on last month's poll.
Labour, meanwhile, is up 3.6 points to 30.3% - its highest result in a TPU-Curia poll in 16 months.
The Greens are down by 0.6 points to 10.4%, while ACT is up 0.9 points to 9.7%.
New Zealand First is on 7.6%, up by 0.8 points, and Te Pāti Māori is down 2 points to 3%.
Outside of Parliament, TOP is on 2.5%, while the combined total for other parties is 1.6%.
While National would lose four seats and Labour would gain five, it would not be enough to unseat the coalition.
National's 44 seats, ACT's 12 seats, and New Zealand First's 9 seats means the coalition would have a total of 65.
Labour would have 38, the Greens 13, and Te Pāti Māori 6.
Christopher Luxon has also taken a hit as preferred prime minister, dropping five points to 27.7%.
But he is still ahead of Labour leader Chris Hipkins, who is on 16.9% (up 4.3 points). Green Party co-leader Chlöe Swarbrick is in third place at 9.9% (up 2.7 points), followed by NZ First's Winston Peters on 8.4% (up 1.7 points).
The poll was conducted by Curia Market Research for the Taxpayers' Union. It polled 1000 random adult New Zealanders by phone (landlines and mobile) and online between October 3 to 7, and has a maximum margin of error of +/- 3.1 percent.
A total of 3.4% of people were undecided on the party vote question.
Polls compare to the most recent poll by the same polling company, as different polls can use different methodologies. They are intended to track trends in voting preferences, showing a snapshot in time, rather than be a completely accurate predictor of the final election result.
