New Zealand Prime Minister Jacinda Ardern said Thursday she will not seek re-election to parliament at this year's general election and plans to step down as prime minister early next month.

The Labour Party leader said in a televised statement that she no longer has "enough in the tank" to perform her role to the fullest and will end her term as prime minister no later than Feb. 7.

A general election will be held on Oct. 14, she added.

New Zealand Prime Minister Jacinda Ardern announces her resignation on Jan. 19, 2023, in Napier, New Zealand. (Getty/Kyodo)

After serving more than five years as the country's leader, an emotional Ardern told reporters in the North Island city of Napier that over the summer, she had "hoped to find a way to prepare not just for another year, but another term," but had been unable to do so.

"I know what this job takes. And I know that I no longer have enough in the tank to do it justice," she said.

The New Zealand Labour Party will hold a leadership vote on Sunday. According to Ardern, Deputy Prime Minister and Minister for Finance, Grant Robertson, will not put himself forward as a candidate for leader.

The 42-year-old Ardern has been prime minister since October 2017. In her time as leader, she garnered international recognition for her handling of the Christchurch terrorist attack in 2019 and her initial response to the COVID-19 pandemic.

She also made headlines for taking maternity leave after giving birth to her daughter in June 2018, becoming the world's first sitting leader to do so.

But both Ardern and the ruling party have faced waning public support over the past year, with recent polls placing Labour behind conservative rivals amid an economic fallout from the pandemic and a housing crisis, among other domestic issues.

A Kantar One News Poll in December saw the opposition National Party ahead of Labour by 5 percentage points, while Ardern posted her lowest popularity as preferred prime minister since becoming party leader in August 2017.

Ardern, however, said she was not stepping down because she did not believe Labour could win the next election but because she believed it could.

Bryce Edwards, a political analyst and lecturer at Victoria University of Wellington, told Kyodo News that Thursday's announcement shocked New Zealanders, but it was not a surprise to some.

"Although no one really saw this coming today, there has been speculation that she might stand down over the last few months," said Edwards, pointing to Labour's decline in the polls and increasingly negative media coverage of Ardern.

Citing the National Party's performance in recent polls, Edwards said experts expect a change of government to National in October, adding that it would have been a very tough campaign for Ardern to turn around.

As the party looks to find her replacement, Edwards says no politician will find it easy. "She really did tower above everyone else in New Zealand politics," he said.

Ardern will retain her position as a lawmaker until April, a written statement said, avoiding the need for a by-election in her constituency ahead of the October election.