Four months out from the New Zealand election, National have ousted unpopular leader Simon Bridges, replacing him with untested agricuture spokesman Todd Muller.
Mr Muller was victorious in a leadership ballot at an emergency caucus meeting on Friday, called after the opposition slumped to decade-low polling results.
Nikki Kaye has been elected deputy, replacing Paula Bennett.
In keeping with the party's conservative nature, both Mr Bridges and Mr Muller kept a low profile through the week.
Mr Muller was barely sighted, but laid out the premise for his challenge in an email to the 55 National MPs, saying New Zealand faced "the most enormous challenge since the end of the Second World War".
"Labour has failed to deliver on every measure it has set for itself in Government. This will not change and the consequences of it being re-elected at this time will be catastrophic for two generations," he wrote.
"Our communities and our economy are at stake. It is essential National wins this election.
"I share the view of a majority of colleagues that this is not possible under the current leadership.
"I believe I am best placed to earn the trust of New Zealanders by September 19."
Mr Bridges called the challenge a distraction, and Ms Ardern's poll bump a temporary one due to her enormous exposure during the height of the COVID-19 crisis.
Australian Associated Press