Key Points:

Aucklanders and men disproportionately support National Party leader John Key.

The rest of the country and women disproportionately support Labour and Prime Minister Helen Clark.

The latest Herald-DigiPoll survey has 55. 1 per cent of Aucklanders supporting National and 33.4 per cent backing Labour.

That compares to overall support of the parties of 51.3 per cent for National and 38.1 per cent for Labour.

The Maori Party also gets more support in Auckland (4.2 per cent) than in the rest of the country (2.4).

The same poll shows 55.7 per cent of men support National (higher than its total party vote) and 34.2 per cent of men support Labour (lower than total).

For women, there is less of a gap: 46.8 per cent support National and 42.1 per cent favour Labour.

The Green Party and Maori Party also disproportionately appeal to women while the New Zealand First party attracts men.

Helen Clark has lost support in Auckland as preferred prime minister - though she is still well ahead of Mr Key. In last month's poll, she was preferred Prime Minister by 50.8 per cent of voters overall but was disproportionately favoured in Auckland, with 54.1 per cent support.

The poll this month sees her with 48.7 per cent overall, ahead of Mr Key on 36.7 per cent, but her support in Auckland has fallen to 43.1 per cent, and Mr Key's is at 41.1 per cent.

The accompanying graphic shows that National's party vote, while only shifting 0.1 per cent in the past month, is healthy enough to secure an absolute majority in terms of Parliamentary seats.

This is largely a factor of the failure of the Greens to get above the 5 per cent threshold for the first time since July this year.

Also, National is helped by the low polling of New Zealand First - 2.1 per cent - though party leader Winston Peters' strong showing in the preferred prime minister ratings could lift his party's hopes.