By Ana Nicolaci da Costa
WELLINGTON (Reuters) - New Zealand's opposition Labour party is gaining momentum that could allow it to form a coalition government with partners of its choice, an average of political polls showed on Monday, with a key nationalist party at risk of losing its kingmaker role.
Crucially, the result suggests that Labour, now running neck-and-neck with the National Party, may be in a position to form the government after Sept. 23 elections without having to rely on the controversial nationalist party.
National, however, would still be heavily reliant on the nationalist New Zealand First, whose support is also waning. Although both parties are open to forming a coalition with it, it has not said which major party it will back.
Labour's average rose to 39.8 percent and the Greens' average was 6.2 percent, Monday's figures showed, putting the two parties, which share a working agreement, comfortably ahead of National's 41.6 percent.
A party, or combination of parties, needs 61 of Parliament's 120 members in order to form a government in New Zealand's German-style proportional representation system.
The averages suggest Labour and the Green Party would garner 57 seats, compared to National's 51.
"If National happen to drop a bit further, they won't have any chance of forming a government because they don't have as many coalition options as Labour," said Bryce Edwards, a political analyst at Victoria University in Wellington.
"Labour, by contrast, is moving up, and if it gains another couple of percentage points in the polls, will have multiple coalition options," he added.
Only weeks ago, the New Zealand First Party, led by the outspoken Winston Peters, was expected to be the kingmaker in the formation of government after the vote.
But a controversy over mistaken overpayment of superannuation to Peters has hurt support, while voters have also been drawn to the Labour party after it switched leaders on Aug. 1.
Although the average of polls shows New Zealand First remains decisive in the formation of the next government, the situation could change if its loss of momentum continues, analysts say.
New Zealand First's average fell to 8 percent, down from 9.1 percent on Friday.
"Certainly New Zealand First, if they are somewhere in the 5 percent to 7 percent range, there will be a good chance of them no longer being a kingmaker after the election," Edwards added.
Support for the party fell to 6.6 percent in a poll released on Sunday, following a drop to 8 percent in another poll last week. Both polls were used to calculate Monday's average.
(Reporting by Ana Nicolaci da Costa; Additional Reporting by Charlotte Greenfield; Editing by Clarence Fernandez)