Labour slumped to its lowest in 15 years in the latest Herald DigiPoll survey as men abandoned the party.
The party fell four points from June to 26.5% support.
National rose 4.5% to 54.9% — enough for the party to goven alone and gain 10 MPs.
On the face of things, the situation looks bleak for Labour, but commentator Matthew Hooton argues 2011 polls almost universally over-estimated National's support. And a 3News-Reid Research poll, also released over the weekend, found National (49.4%) and Labour (26.7%) support stable.
The Herald Digipoll found Prime Minister John Key's populartiy as preferred prime minister was an all-time high of 73.3%, compared with Labour leader David Cunliffe on 10.5%.
The second-most-preferred PM out of Labour MPs is David Shearer, with 2.2%t, followed by Jacinda Ardern on 1.4%.
The poll followed on the heels of Labour's education policy for small class sizes and a subsidised computer or every child, and Mr Cunliffe's apology for being a man ("I'm sorry for being a man, because family and sexual violence is overwhelmingly perpetrated by men," he said.)
Labour's total support is down from 30.5% in June, but it is disproportionately down among male voters, with only 23.9 per cent of men backing Labour, compared with 29.1 per cent of women.
The Greens also fell, to 9.9%
Internet-Mana to 2.2% — enough to bring Internet Party leader Laila Harre and Mana's Annette Sykes into Parliament if Hone Harawira holds his Te Tai Tokerau seat.
NZ First was on 4.6%.
Other parties were in the margin of error.
The poll of 750 decided voters was taken between July 10 and July 17. Undecided voters were 11.5%. The poll has a margin of error of plus or minus 3.6%.