Chris Hipkins will be sworn in as Prime Minister again this weekend as Government coalition negotiations between ACT, NZ First and National drag on.
Hipkins will be reappointed at about 1pm on Saturday, although there will be no formal ceremony.
The formality comes due to a constitutional quirk. The Constitution Act states when a minister ceases to be a MP, that person can continue to hold the ministerial office "until the expiration of the 28th day after the day on which that person ceases to be a member of Parliament".
That means 28 days after the end of election day, which is Saturday.
Following consultation with incoming Prime Minister Christopher Luxon, who is locked in coalition negotiations with NZ First and ACT, Hipkins had written to the Governor-General "to advise her to reappoint the current ministry to operate in caretaker mode until the new government is appointed", he said in a statement.
Hipkins said ministers would continue in their current portfolios, except for outgoing Foreign Affairs Minister Nanaia Mahuta who had not been re-elected and would leave office on Saturday.
Grant Robertson would be appointed to the Foreign Affairs and Disarmament and Arms Control portfolios, while Willie Jackson would take over Mahuta's Associate Māori Development Minister delegations, Hipkins said.
"This solution to a constitutional quirk has been amicably agreed and we continue to consult closely with the incoming Government on all key decisions."
Hipkins' Labour lost last month's election but he was still reappointed as the party's leader earlier this week.