Labour has been facing major political challenges ahead of the Oct. 14 election. For almost a year, the party has polled behind the center-right National Party, led by Christopher Luxon, a former aviation executive. As of December, support for Labour was at 33 percent, compared with 38 percent for the National Party.
Still, Ms. Ardern has remained personally popular with the electorate. She has regularly outperformed Mr. Luxon in polls as most New Zealanders’ “preferred prime minister.”
Mr. Luxon said last month that the polls showed New Zealanders felt the country was going in the “wrong direction.” He added: “What they can see is a government that’s just not getting things done.”
Ben Thomas, a political commentator and former press secretary for the National Party, said her resignation would come as a surprise for many New Zealanders and could spell disaster for the Labour Party.
“She’s Labour’s number one political asset,” he said. “It would very much be a personal decision to step down, as opposed to a considered strategy about what would be best for Labour in the election.”
In resigning almost a year before a general election, Ms. Ardern follows closely in the footsteps of her predecessor, then-Prime Minister John Key, who stepped down in 2016, allowing his deputy, Bill English, to take his place as leader of the National Party and prime minister.
But there is no obvious successor to Ms. Ardern. Grant Robertson, Labour’s deputy leader, will not seek the leadership, Ms. Ardern said. Any candidate seeking to lead Labour must have the support of at least two-thirds of its lawmakers, a requirement that raises the prospect of a power vacuum, prolonged infighting and a relative newcomer, at least in voters’ eyes, leading the party and the country.
This is a developing story and will be updated.