Jacinda Ardern, the prime minister of New Zealand, faced her first major crisis Friday over her handling of a gaffe-prone minister’s resignation.

Ms Ardern swept to power on a wave of "Jacinda-mania" late last year, with her centre-left Labour Party leading a coalition that promised "a government of change".

The optimism surrounding her administration was enhanced in June when she gave birth to daughter Neve, becoming only the second female leader in the world to have a baby in office.

But her lustre  has dimmed in recent weeks amid policy squabbles with coalition partners and plummeting business confidence.

Ms Ardern revealed Friday that her government had suffered its first casualty, with Broadcasting Minister Clare Curran resigning after using a private email account to conduct government business.

Ms Curran, who had been disciplined twice previously for failing to declare meetings, said she faced "intolerable pressure" and did not want to become a distraction for the government.

But it was the way Ms Ardern dealt with the problem that drew most criticism, with opponents accusing her of misleading the public.

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Asked on talkback radio on Friday morning whether she was considering firing Ms Curran, she replied: "No, I think she’s paid her price.

"We want to make sure that you don’t set the bar so high that you have a situation where you show a bit of human frailty and you lose your job over it."

In fact, Ms Ardern had accepted Ms Curran’s resignation the previous night but failed to mention it during the 10-minute interview.

Ms Ardern later insisted that she answered the question correctly but opposition leader Simon Bridges zeroed in on her evasiveness, saying she had mishandled the affair.

"The prime minister needs to explain why she misled New Zealanders this morning by saying Ms Curran’s job was safe when Ms Curran says she resigned last night," he said.

"This whole saga has seriously damaged the credibility of both the prime minister and the government."

Another of Ms Ardern’s ministers, Meka Whaitiri, has stood aside from her customs portfolio while under investigation for an alleged physical altercation with a staffer.