KEY POINTS:
Labour's tax-cutting Budget has had no immediate impact on its poll rating in today's Herald-DigiPoll survey, the first major poll that includes a large post-Budget sample.
The economy has moved into top spot as the issue most likely to influence voters in this year's election, just nudging out tax cuts, which is the second most important issue.
Labour has moved down one point to 36.2 per cent but National has also moved down fractionally, by 0.6 to 51.5.
The gap between the two main parties has barely budged from last month's poll: 15.3 points, compared with 14.9 last month. National would still be able to govern alone.
National leader John Key continues to poll just ahead of Helen Clark as preferred prime minister, 44.6 per cent to 42.3 per cent.
If anyone received a lift from the Budget, it was New Zealand First leader Winston Peters, who claimed significant gains for the elderly.
His personal ratings as preferred prime minister more than doubled to 6.7 per cent.
But that boost has not been replicated in support for his party (1.9 per cent, up 0.4 points).
On those figures, unless Mr Peters won Tauranga or another electorate, NZ First would not make it back into Parliament.
The poll of decided voters was taken over three weeks in May. Two-thirds of respondents were polled before the Budget and almost one-third (418 people) after it. The margin of error on the post-Budget sample is bigger than the pre-Budget sample.
The support levels for the parties changed slightly in the samples taken before and after the Budget. Labour was on 36.5 per cent before the Budget, and 35.3 per cent after it.
National was on 51.7 per cent before the Budget and 51.2 after it.
On the basis of this poll the Greens would comfortably get over the 5 per cent threshold and return to Parliament with eight MPs, two more than now.
The poll's pre- and post-Budget movements were more pronounced for Helen Clark and Winston Peters in the choice of preferred prime minister.
Helen Clark dropped 3.6 points and Winston Peters jumped 4.3 points in the post-Budget sample.
Overall, compared to last month's poll, Mr Peters is up 3.5 points, Mr Key is down 3.4 and Helen Clark is down 3.
Economic news dominated the headlines in May with the price of petrol passing $2 a litre and a lot of coverage on interest rates and stress on household budgets.
The Government announced a delay in including liquid fuels in the emissions trading scheme,which National announced it would not support.
The head of the Immigration Service, Mary Anne Thompson, resigned in disgrace. And Finance Minister Michael Cullen set out plans for $10.6 billion in tax cuts over three years.
Translated to seats in the House, National would get 63 and could govern alone.
When respondents were asked which issue was most likely to influence their vote at the election, 26.7 per cent said the economy, 22.5 per cent said tax cuts and 11.7 per cent said hospital waiting lists.
Mr Key said last night that the economic issues the country was facing were weighing directly on the polls. "On the back of that, the Budget doesn't appear to be having any major impact because the dominant factor is the economic malaise that is washing over the country."
Helen Clark could not be contacted.
* The poll of 1279 respondents was taken between May 5 and May 28 and the margin of error on the total sample is 2.7 per cent. The margin of error on the 418 polled after the Budget is 4.6 per cent. The percentage of undecided respondents was 13.8 per cent.
