Last week, Ms Ardern announced she'd finally set a date for the wedding, more than two years after Mr Gayford proposed.

She has yet to reveal the actual date, saying she wants guests to get a jump start on accommodation in the small city.

"I'm not sure that I want a situation where before I've invited people who really want to be there I just broadcast it out," she told breakfast television program The AM Show.

"Accommodation is slightly limited in Gisborne."

After being congratulated on picking the Tairawhiti for the wedding, she responded: "Where else?"

Ms Ardern and Mr Gayford spend their summer holidays in the region, known for its laidback lifestyle, beautiful beaches and fine summer weather.

The wedding has been keenly anticipated since the pair were engaged at Easter two years ago.

Mr Gayford popped the question in the same region, on the nearby Mahia peninsula.

Weddings featuring a current head of government are exceedingly rare: Australia has never had a sitting prime minister tie the knot.

Ms Ardern also became a first-time mother while in office when she gave birth to daughter Neve in June 2018.

A gift from the two-year-old featured on the prime minister's Instagram on Sunday for Mother's Day.

"Happy Mothers Day. I love you and going to the water park. Love Neve xxxxx," the card read.

Australian Associated Press