The backers of a poll say John Key is losing support among women.
A Fairfax/Ipsos poll has 39% of women supporting National, with females more likely to see the prime minister as a polarising figure following issues such as the class sizes controversy.
It is difficult to quantify a trend, as the Fairfax/Ipos poll is the first of its type.
However, Fairfax points to other polls before the last election that showed 50% of women supported National.
"Women swing voters have become particularly crucial in modern New Zealand elections," Otago University political scientist Bryce Edwards told NBR ONLINE.
"John Key will be well aware of that, and also well aware that his relatively strong performance in winning women over to National in 2008 was absolutely crucial to getting into government," Mr Edwards said.
"His strong appeal to women swing voters, was both ideological – not being too right-wing – and not being too much of a boring traditional politician.
"More recently he's been losing these qualities," said the pol sci lecturer and NZ Politics Daily blogger.
"First, economic austerity has pressured Key to become more hardline in responding the fiscal situation.
"And, second, these days he's been somewhat less of a 'blokey' non-politician," Mr Edwards said.
"Perhaps counterintuitively, it was when he was most 'blokey' – wearing t-shirts, strutting on the catwalk, being highly casual, and generally acting like 'the guy next door' – that John Key probably had the most appeal to female swing voters.
"To appeal again to that demographic, he needs to stop playing at being a statesman on the world stage, and get back to his winning formula of being a 'common man' engaged with the general electorate.
"But perhaps more substantively, he will appeal more to such women voters when and if he's able to cease his association with austerity measures such as government spending cuts."
Fairfax also said Mr Key had become "an increasingly becoming a polarising figure" but again, with the poll being the first in a series, the trend is hard to pin down.
There are limits to the disillusionment. 63% think Key has a clear vision for the country, and was a strong and effective leader, according to Farfax/Ipsos.
In terms of party vote support, the poll of 1000 eligible voters (phoned July 19-23) finds, like other recent surveys, that the combined Labour-Greens block is neck-and-neck with National:
NZ First: 3.6%
United Future: 0.1%
A survey of public polls carried out by Curia's David Farrar had the following standings as of July 3:
National: 47.2% (60 seats)
Labour: 32.2% (41 seats)
Greens: 12.3% (16 seats)
NZ First: 3.9% (0 seats)
Maori: 1.5% (3 seats assuming it holds its 3 electorates)
Mana: 0.8% (1 seat assuming Hone Harawira holds Te Tai Tokerau)
ACT: 0.5% (0 seats, or 1 if John Banks holds Epsom)
United Future: 0.3% (1 assuming Peter Dunne holds Ohariu
(Conservative Party not listed)