National and Greens gain support

National's tax-cut policy has arrested Labour's leap in support after its student loans and family tax relief announcements, the latest Herald DigiPoll survey suggests.

Overall, Labour is comfortably ahead on 45.3 per cent, up 1.4 points from last month's poll.

National is on 36 per cent, down 1.5. The difference between the two is 9.3 points.

But comparisons between the two parts of the poll tell a different story. Part of the poll was conducted before National's tax announcement on Monday and the other part after it.

Late last month, Labour promised it would wipe interest on student loans.

After its tax package and before National's policy release, DigiPoll had conducted almost 40 per cent of its polling, which showed dramatic gains for Labour. It had stretched its lead to 13.7 points (Labour 46; National 32), well up on its 6.4 point lead in the last poll.

The larger polling segment, taken after National's tax announcement, also has Labour leading National, but by a much reduced margin of 6.6 points.

The correlation between major tax announcements and big voter swings may also be reflected in the fact that tax is again the number one issue facing the country, ahead of health and education.

Figures are of decided voters only of the 1000 people polled - 9.8 per cent of respondents were undecided, refused to say or did not know.

The poll results for the party vote: Labour 45.3 per cent; National 36; Green 6.4; New Zealand First 6.1; Maori Party 2.2; United Future 1.3; Act 0.9; Progressives 0.6.

National Party leader Don Brash said through a spokesman that the poll was a "positive early response" to the tax package and he expected the polls to close further as people came to understand how they could get ahead with National's policy.

If the poll were translated to seats, National would have no show of forming a Government. Labour would be able to form a coalition with either the Greens or New Zealand First to get a majority of 61 seats.

To boost the Greens' flagging support, Prime Minister Helen Clark agreed to a symbolic public outing with Greens co-leader Jeanette Fitzsimons last week.

That may have had some bearing on the Greens' marked improvement in the DigiPoll, doubling their support from 3.2 per cent to 6.4 per cent and pipping New Zealand First as the third most popular party.

Helen Clark's rating as preferred Prime Minister climbed 5.5 points to 59.3 per cent of decided voters, Dr Brash improved 0.8 points to 29.1, and New Zealand First leader Winston Peters fell 4.1 points to 6.2.

National's support among women and among Aucklanders is well below its overall support.

Only 31.1 per cent of decided women support National, compared with 51.3 per cent who support Labour. Only 29 per cent of decided Auckland voters support National, compared with 49.2 for Labour.

A further breakdown shows that National's disproportionately low support among women was strongly evident in the first segment of the poll, before Dr Brash made his comments about going easy on Helen Clark in the TV One debate. It actually increased slightly among women in the second segment.

DigiPoll director Gabriel Dekel said the gaps between the poll segments were significant and correlated to the political announcements over tax.

The poll of 1000 respondents was conducted between August 18 and 24. The margin of error overall is 3.1 per cent. The polling sample in the first segement was 388 and the margin of error is 5 per cent. The polling sample in the second segment was 612 and the margin of error 4 per cent.