After an extremely challenging 2019, New Zealand Prime Minister Jacinda Ardern has decided to cross the Tasman for her summer holiday.

In January, Ms Ardern, her fiance Clarke Gayford and their one-year-old daughter Neve will travel to Australia, where they are expected to holiday close to Sydney instead of her usual preferred spot, the Sunshine Coast.

Before heading to Australia Ardern will spend Christmas and New Year's near Gisborne on the east coast of New Zealand with extended family.

The appeal of an Australia holiday lies in the relative anonymity she experiences there, Ms Ardern told AAP.

New Zealand Prime Minister Jacinda Ardern, fiance Clarke Gayford and their daughter Neve. Photo / Getty Images

"It's not to escape or anything like that because in Gisborne we have a wonderful time," she said.

"It's just we don't have to take our security. We can be by ourselves. It's really nice. We can be a bit more spontaneous."

Ms Ardern dealt with two major national crises this year; the mass shooting of 51 people in Christchurch in March by white supremacist Brenton Tarrant and this month's White Island volcano tragedy that killed 16 people with two more missing and presumed dead and dozens badly injured.

She plans to wed fiance Mr Gayford next year and has brushed off suggestions that the couple might get hitched on their summer holiday.

"We won't be getting married in Australia," she says.

"Planning? Maybe if we manage to turn our minds to it. But that doesn't sound very relaxing to me."