Meka Whaitiri's defection from Labour has thrown wide open the contest for the normally safe Labour seat of lkaroa-Rāwhiti.
Whaitiri remains in Parliament as an independent MP but intends to contest her seat, which spans much of the east of the North Island, for Te Pāti Māori.
The party swap also focuses attention on Labour's Māori caucus, which now faces close races in several Māori electorates.
"The decision to cross the floor is not an easy one, but it's the right one," Meka Whaitiri said at Waipatu Marae, dropping the announcement few saw coming.
Her former Labour Party colleagues were stunned and Prime Minister Chris Hipkins was given no heads-up.
Labour's Māori caucus co-chair Willie Jackson was left - in his words - sad.
"We're all disappointed and surprised, I suppose, with what happened," he said.
"She hasn't said anything to us, she never, never mentioned that work 'emancipation' to me but she was always a strong advocate for Māori."
Whaitiri had been a Labour MP for a decade, and before that, worked for the late Parekura Horomia.
She was effectively his protégé in an electorate that - apart from a blip in 1996 - had been staunchly Labour.
Commentator and former Labour staffer Shane Te Pou said many in the party may feel betrayed.
"We'll see how things settle down, there might be a sense of betrayal.
"Meka was elected on a Labour Party ticket, a Member of Parliament for Labour, following Parekura. I think there might be a bit of mamae out there."
So why has she ditched Labour?
Whaitiri gave few specifics, simply describing the move to Te Pāti Māori as a homecoming.
She spoke of returning to her Kahungunu whakapapa and of kotahitanga.
"It's my calling, it's who I am as a Māori, proudly so.
"As a wāhine Māori from a place that has borne great leaders, and particularly from a marae that has brought great leaders, and actually gave raise to the very first Māori Parliament, the kotahitanga movement.
"So for me, it's coming home," Whaitiri said.
Political commentator Morgan Godfery said the frustrations of being Māori in a large party like Labour could have taken a toll.
"They're all the compromises small and large that you have to make, they all accumulate and take their toll.
"So two decades later it's not surprising to say 'I've had enough'."
Te Pāti Māori was ecstatic to have a government minister defect to it as it makes a strong push in the seven Māori electorates.
Co-leader Rawiri Waititi holds Waiariki, while his counterpart Debbie Ngarewa-Packer only narrowly missed taking Te Tai Hauauru last election.
Whaitiri won Ikaroa-Rāwhiti with a commanding majority in 2020, but Labour had 67 percent of the party vote.
Te Pāti Māori president John Tamihere said he would put his house on Whaitiri keeping the seat.
But she said she would have to prove herself.
"We've enjoyed having the seat and it's not a seat to be taken for granted and we will work really hard in this election to retain and to win it for Te Pāti Māori."
Labour was gearing up for a fight, though.
Willie Jackson said he was already talking to potential candidates.
"I'll be surprised if we lost the seat, given the history of the seat. Meka ... was mentored by Parekura Horomia and he was Labour through and through."
As his Māori caucus licked its wounds, Willie Jackson said he was confident there would be no more defections.