By Ana Nicolaci da Costa and Jane Wardell
WELLINGTON (Reuters) - The race for New Zealand's September election has tightened significantly only days after the appointment of New Zealand's new opposition Labour Party leader Jacinda Ardern, a poll said on Wednesday.
Labour has jumped 9 points to 33.1 percent, its highest level since 2014, while the Nationals lost 0.8 percentage points to 44.4 percent - their lowest level of voter support for more than 10 years, said a Newshub/Reid Research poll.
Personal support for Ardern, who took the leadership of the struggling Labour Party last week, showed her closing in on Prime Minister Bill English in the race for the top job. Ardern surged 19.6 points from her role as deputy to 26.3 percent, putting her just 1.4 percentage points behind English.
Analysts described the move to install her as leader as a potential game-changer ahead of a Sept. 23 election that had been seen as a slam-dunk for the centre-right National Party, which has been buoyed by some of the strongest economic growth among advanced countries.
Ardern became her struggling party's youngest leader, five days after her 37th birthday, in a bid to end the Nationals' decade-long hold on power.
New Zealand's electoral system means that either the National Party or the Labour Party will likely need to sign up the right-wing NZ First Party as a coalition partner to gain enough seats to control the parliament.
In an election campaign marked by an unusual degree of turmoil, there was another shock resignation less than an hour before the release of the latest poll when the scandal-hit co-leader of the minority Greens Party stepped down.
Greens co-leader Metiria Turei had been under public and political pressure to step down after admitting last month that she had committed benefit fraud as a solo mother in the 1990s in order to increase the size of her welfare payments.
Turei said the subsequent scrutiny of her family had become "unbearable" and stepped down shortly before the poll was published, which showed support for the Greens had slumped 4.7 points to 8.3 percent.