"Yeah it is a surprise. I think she's looked after the country over some pretty difficult times," said one unidentified resident in Christchurch.

Ardern's empathetic leadership style was cemented by her response to the mass shootings at two mosques in Christchurch in 2019 that killed 51 people injured 40. She won plaudits across the political spectrum for her handling of the COVID-19 pandemic, which saw the country face some of the strictest measures globally but also resulted in one of the lowest death tolls.

A ruling New Zealand Labour Party vote for a new leader will take place on Sunday (January 22); the party leader will be prime minister until the next general election. Ardern's term as leader will conclude no later than Feb. 7 and a general election will be held on Oct. 14.