KEY POINTS:
National leads Labour in every age group and every income band in the August Herald-DigiPoll survey, but its dominance is reducing among middle-aged people and higher-income earners.
With National still polling 50 per cent overall, it enjoys good support across the board.
However, since the July DigiPoll survey, which gave National a 24.6 percentage point lead - dramatically reduced to 13.7 points in this month's poll - John Key's party has suffered a loss of support in areas it might normally think might be skewed in its favour.
Although the numbers of people in each age bracket are small and therefore the analysis of the figures is indicative only, National has notably lost support in the 30-39, 50-59, and 60-69 age groups since July while Labour has picked it up.
For instance, in July National polled 60 per cent or higher in all three of those age groups, but this month the party has under 50 per cent in both the 50-59 and 60-69 groups, and 51.9 per cent support in the 30-39 age group.
Across income bands, National has lost support in every category.
However, the drop is most marked in the $80,000 to $100,000 bracket as well as the over $100,000 category.
Again, those brackets encompass only small numbers of people so should be read as indicative.
Prime Minister Helen Clark has taken heart from the recent narrowing of the polls and she will be keeping a close eye on how the Greens are faring.
Labour is likely to need the help of the Greens if it is to form the next government and in the DigiPoll survey the potentially crucial support party is right on the edge of the threshold to enter Parliament - registering 5.1 per cent support.
A wildcard in the mix which gives Labour further cause for optimism is the fact that a high 17.1 per cent of those polled were undecided about which party to vote for.
The Maori Party, another grouping which could be crucial in post-election negotiations, registers 3.1 per cent support and is highly likely to claim at least four electorate seats.
Act has picked up 2 percentage points in the poll to reach 2.3 per cent support as leader Rodney Hide has been in the spotlight challenging Winston Peters.
The economy remains the issue most likely to influence voters at the election, with 24.7 per cent of those surveyed putting it at the top of their list - perhaps indicating that household budgets are still feeling the pinch.
Law and order remains the second most important issue among voters, and tax cuts are third.
