KEY POINTS:
Winston Peters is in trouble on two fronts - unanswered questions about big-business donations and a low rating for his New Zealand First party in the Herald poll of polls.
This far before the 2005 election New Zealand First was averaging 9 to 10 per cent in polls.
In the four most recent published polls its average was 3.6 per cent.
Whether the party can clear the 5 per cent party vote hurdle it needs to stay in Parliament looks to be touch and go, even with a better timed campaign than the premature peak in 2005.
The Greens' average since the 2005 election has only once dipped below 5 per cent and then by only 0.1 per cent. Their latest four-poll average is 5.9 per cent.
The Maori Party, which draws its strength from the electorate vote in the Maori seats, does not need to clear 5 per cent on the party vote. In 2005, it won one more seat than its party vote entitled it to. That "overhang" seat lifted Parliament's total from 120 to 121 MPs.
That was on 2.1 per cent of the party vote, exactly the latest poll of polls average. If it adds to its haul of Maori seats this election, its "overhang" would likely rise.
Even at 3 per cent of the party vote, it would get two "overhangs" if it won six Maori electorate seats.
Act's and United Future's most recent poll-of-poll averages have been 0.9 per cent and 0.4 per cent respectively. They will stay in Parliament if their leaders hold their electorate seats. Jim Anderton is at 0.1 per cent - a level which would make him an "overhang" if he holds Wigram.
The huge gap between the major parties has narrowed a little since the poll of polls was last published on July 1.
National is down from 53.9 per cent to 51.6 per cent, and Labour up from 30.5 per cent to 34 per cent.
* The poll of polls is a rolling average of the four most recent polls at each point. Since five polls are included, one is necessarily missing from each point and sometimes a poll will feature twice. The five are Herald Digipoll, TV1 Colmar Brunton, TV3 TNS, Fairfax Neilson and Roy Morgan (once a month). UMR was included in earlier data, but has withheld data since April.