Analysis - Jacinda Ardern has arrived at hospital to have her baby and Winston Peters is in charge of the country.
Winston Peters Photo: RNZ / Richard Tindiller
While having an acting prime minister is not unheard of, the circumstances under which it has happened are highly unusual - a woman has had a child while in office only once before, the Pakistani Prime Minister Benazir Bhutto in 1990.
Since being elected Ms Ardern has become an international political figure and there will be intense interest in the Prime Ministerial baby.
This has all been a new challenge for her staff as they try to balance the inevitable domestic and international media demands, while trying to make the birth as "normal" as possible for Ms Ardern and partner Clarke Gayford.
There is no blueprint but the offices of Ms Ardern and Winston Peters have been at pains to play down the handover as "business as usual" in the weeks leading up to the birth.
Prime Minister Jacinda Ardern on her way to the post-cabinet news briefing on 11 June. Photo: RNZ / Chris Bramwell
The Prime Minister's Office is on the ninth floor of the Beehive, where her staff will remain. Mr Peters is currently on the seventh floor and that's where he and his staff will stay during the six weeks, working in close contact with the PMO.
He is a very experienced politician, having served as foreign minister under two administrations, and deputy prime minister in a National government in the 1990s, and he has every reason to ensure the six weeks runs smoothly under his watch.
Mr Peters can have a combative relationship with the media and all eyes will be on the style he adopts while acting prime minister; he can certainly play the statesman when it suits him and that would be the expectation as he fills in for Ms Ardern.
Prime Minister Jacinda Ardern in Northland in early June. Photo: RNZ / Dan Cook
She however will not be completely removing herself from the role, and will continue to receive all Cabinet papers and Cabinet committee papers, which means she can keep an eye on everything getting signed off at the highest level.
Ms Ardern wrote formally to Mr Peters last month outlining her expectations of their respective roles.
In the event of something of "significant political, strategic or public interest, or national security", Ms Ardern would be consulted and involved in major decisions that might be needed.
Mr Peters will run the "day to day" business of the government, that includes the prime minister's media and public engagements, chairing Cabinet and fronting Parliament's question time.
He will be limited by decisions made by the Labour dominated Cabinet and then of course Parliament, which has to vote for any matter requiring legislative change.
Under these arrangements he will not have the ability to make any significant decision not already on the government's agenda - if something urgent or significant comes up Ms Ardern will have some involvement.
That may include a disciplinary matter - all Cabinet ministers serve at the pleasure of the Prime Minister regardless of the party they're with. Ms Ardern has said she would want to be involved with anything relating to Labour Party ministers.
The Cabinet Manual deals with the responsibilities of an acting Prime Minister in two short paragraphs:
"If the Prime Minister is unavailable or unable to exercise the statutory or constitutional functions and powers of the office, the deputy prime minister can, if necessary, exercise those powers and functions.
"As acting prime minister, the deputy prime minister may exercise other prime ministerial functions and powers, in consultation (where appropriate and practicable) with the prime minister."
Realistically Ms Ardern will be hoping for a smooth six weeks while she's away, and Mr Peters will not want to be remembered for a car crash of a time.
Of course he is still the foreign minister and if he is out of the country then the prime minister role passes to Labour Party deputy, Kelvin Davis.
If his performance at select committee recently is anything to go by there will be plenty of work behind the scenes to make sure he is adequately briefed to handle run of the mill questions from the media, or that other senior ministers like Grant Robertson front question time.
The National Party is biding its time; it still holds Winston Peters responsible for not giving it the numbers to govern after the election and will highlight any mistakes he makes.
But it won't want to make the birth of the prime minister's child too political, as there will be plenty of goodwill for the new family - any attacks seen as too opportunistic or critical of the PM for taking time off with a new child may backfire.
Recently describing the impending handing over of the reins as a "snooze fest", leader Simon Bridges will of course still be keeping a watching brief on Winston Peters as prime minister, ready to pounce on any mis-step.
Within 24 hours of making the snooze fest comment, Mr Bridges was happily reassessing the political interest this transition could generate, claiming New Zealand First was acting in full defiance of the prime minister, boding ill for the coming weeks.