Ardern became only the second leader of a country to have a baby while in office when she gave birth to her daughter Neve on 21 June. When she announced her pregnancy, shortly after becoming prime minister last year, she said she would take six weeks of maternity leave.

She officially took back the reins from her deputy Winston Peters at midnight. Ardern did not appear in public on Thursday, but on Wednesday she spoke of her excitement at returning to the job, posting on Facebook about how “lucky” she felt in her role. “I have the privilege of working alongside amazing people everyday. So to them – thank you and see you soon!”

While Ardern was on leave Peters – a 72-year-old veteran politician who is in the process of suing several top government officials for allegedly leaking personal his information – took over.

Most New Zealanders did not know what to expect from the controversial figure, who ensured that Ardern’s Labour Party won last year’s general election when he and his New Zealand First party threw their support behind a centre-left coalition.

Ardern has kept a low profile while on leave, apart from sharing a few videos on Facebook, including one in which she welcomed sweeping government reform for families in a video filmed while she was sitting on her sofa, cradling Neve.

In contrast, Peters’ short tenure was marked by drama.

He called out Australia several times, saying the country was failing to live up to its obligations as a signatory to the UN Convention on the Rights of the Child by detaining a 17-year-old New Zealand minor in a Melbourne detention centre.

Peters also told Australia to change its flag, claiming it had copied New Zealand’s flag decades after it created its design with a Union Jack alongside a Southern Cross constellation. He suggested Australia could instead create a flag featuring a kangaroo on it as well as changing its national anthem to Waltzing Matilda.

He was also on deck as nurses across the country went on strike. Hospitals cancelled elective surgeries and discharged patients early after 30,000 nurses walked off the job in the first such nationwide strike in 30 years. Peters said there was no more money in the government coffers for a higher pay offer.

And he raised eyebrows on talkback radio when he said he did not like the notion of a multicultural New Zealand.

“It’s not a multitude of cultures and a plethora rising up like mushrooms in this country,” he said. “No, we want a New Zealand culture. That’s what I’ve always stood for.”

On Wednesday, his last day as acting prime minister, Peters fat-shamed a colleague in the middle of a parliamentary debate, calling on the Speaker of the House to “throw fatty out” of parliament.

Charles Anderson in Nelson