Ardern, 46, won international acclaim for her handling of the Covid-19 pandemic in New Zealand but the restrictions dented her popularity at home before she stood down from politics in January 2023.

She initially joined Harvard University in the United States, and then moved to Sydney's northern beaches earlier this year.

"I'm delighted to be joining the University of Sydney," Ardern said in a statement.

"I've found myself especially focused on the question of leadership since leaving office -- and how we can better support and encourage the kind of leadership needed to tackle our many global challenges," she said.

The then New Zealand Prime Minister, Jacinda Ardern, participates in a televised debate with National leader Judith Collins at TVNZ in Auckland, Sept. 22, 2020. Photo by Reuters

Ardern is taking up a post as Professor of Practice this month, the university said, offering guest lectures, masterclasses and mentoring.

"Her work will focus on empathetic leadership, social cohesion and civic trust; further developing new approaches to global and values-based leadership," it said.

An international hero of progressive politics, Ardern steered New Zealand through natural disasters, the Covid-19 pandemic and the 2019 Christchurch mosque massacre.

But plaudits abroad did not always match her support at home, which dipped towards the end of her second term in office in the face of deteriorating economic conditions and the Covid backlash.