As debate on her legacy and reasons for her departure rage, Jacinda Ardern has been mobbed by well-wishers outside parliament on her final day as New Zealand Prime Minister.

Hundreds of people, including Labour MPs, government staff and everyday Kiwis packed the forecourt of Parliament House on Wednesday morning.

Several MPs and Ministers were seen wiping away tears as Ms Ardern made her way from the Executive Building – known as the Beehive – for the last time as prime minister.

Stopping to hug members of her team and wave to the crowd, Ms Ardern then took the short trip across Wellington to Government House to resign her commission.

On her side was partner Clarke Gayford, who wrote a tribute to his fiance on Instagram.

“I’m still not sure how I managed to hitch a front row seat in all of this but I remain as always; in awe, in love, relieved, exhausted and so incredibly proud of Neve’s mums superhuman efforts,” he wrote.

“First Bloke out.”

Ms Ardern shocked New Zealand by announcing her resignation last Thursday, saying she was exhausted and couldn’t seek a third term in good conscience.

Many have not taken her comments at face value, including ex-PM Helen Clark, who cited “unprecedented hatred and vitriol” aimed at Ms Ardern during her five years in office.

Local media have reported a tripling of threats towards the PM’s office in the last two years, suggesting a need for ongoing police protection.

In his Instagram post, Mr Gayford took aim at the levels of online hate thrown at Ms Ardern, recalling a response from a Maori elder.

“When asked how they saw that given some of the discourse we’ve seen in ugly places online and via a certain type of public commentator, their response was simply, ‘when you pull the plug on the bath, it’s always the last dregs that are the noisiest’,” he said.

“His comments sit in a sea of the most incredible outpouring of thanks and respect I’ve witnessed first hand over the last few days.

“From spontaneous tears of strangers in airports, to corespondence (sic) staff talking about unprecedented inbox’s full of overwhelmingly positive messages.

“I’ve also learnt that in politics while it might be easier to take the sugar hit path of popularity through division and hate and avoiding unpopular but necessary decisions, there is a better much tougher way of governing in empathy that plants many quiet trees for us all to enjoy the shade of for lots of good years to come.”

Others believe Ms Ardern decided to leave ahead of the October 14 election, reading the tea leaves on her eroding personal and party support.

That challenge now falls to Chris Hipkins, who was uncontested in a ballot to replace Ms Ardern as Labour leader, and was sworn in as prime minister on Wednesday.

– AAP