A general election will be held on Oct. 14, she added.
“This summer, I had hoped to find a way to prepare for not just another year, but another term — because that is what this year requires,” a visibly emotional Ardern said during the statement. “I have not been able to do that.”
Ardern’s term will conclude no later than Feb. 7.
Ardern said she believed her New Zealand Labour Party would still win the upcoming election and added that a vote to elect the next Labour leader would be held on Sunday.
New Zealand Deputy Prime Minister Grant Robertson, who also serves as finance minister, said in a statement he would not seek to stand as the next Labour leader.
Ardern has served two terms as prime minister and became a popular leader on the global stage.
“I am entering now my sixth year in office, and for each of those years, I have given my absolute all,” she said Thursday while fighting back tears. She described the job as a privilege but admitted it was a challenging role.
“But I am not leaving because it was hard,” she said. “Had that been the case I probably would have departed two months into the job.”
Ardern’s zero-tolerance response to the COVID-19 pandemic, which shut New Zealand’s borders for months, was initially praised by local and international politicians and health experts and helped her win re-election in a historic landslide victory in 2020.
But recent polls have put her party behind its conservative rivals amid growing criticism at home that the strategy was too strict. The approach was abandoned once it was challenged by new variants and vaccines became available.
New Zealand’s tight curbs on social gatherings, which were briefly reintroduced to combat the transmissible Omicron variant, even forced Ardern to postpone her own wedding early last year.
Ardern in December announced a Royal Commission of Inquiry would look into whether the government made the right decisions in battling COVID-19 and how it can better prepare for future pandemics. Its report is due next year.
— with files from Global News and the Associated Press