A police spokesperson confirmed the arrest of the 57-year-old woman, adding that she was “currently assisting police with our inquiries into the matter”, reports The New Zealand Herald newspaper.
According to emergency services, the sword outside the Mt Albert electorate office on New North Rd in Morningside was found on the ground outside.
So far, no injuries have been reported, Xinhua news agency quoted the emergency services as saying.
A scene examination will be conducted and inquiries were also underway.
Ardern is presently in Antarctica for a four-day visit celebrating the 65th anniversary of New Zealand’s Scott Base, the country’s only research station in the icy continent.
She is slated to return on Friday.
IANS