King Tuheitia arrives at Parawera Marae where he endorsed Rahui Papa as a candidate in the Hauraki-Waikato electorate.

Labour MP and Maori stalwart Nanaia Mahuta says King Tuheitia's influence over his people will be tested on election day when those in the Hauraki-Waikato electorate cast their vote.

Mahuta's shaking off the Maori King's criticisms of her and his endorsement of Rahui Papa - one of the King's advisors - for the Maori Party in her seat.

Tuheitia made the rare move of endorsing Papa at Parawera Marae, south of Hamilton, on Thursday.

fairfax Labour's Nanaia Mahuta says the King's influence will be tested when Maori go to the polling booth in September.

He called for Mahuta, his cousin, to stand aside and let someone else represent the seat because she no longer has any "mana" in parliament.

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Mahuta has represented the electorate for more than 20 years but says she has never been "formally endorsed" by Kingitanga, the Maori King movement, and Thursday's events were an "odd situation".

REBEKAH PARSONS-KING/FAIRFAX NZ Rahui Papa has been endorsed by Kingi Tuheitia to stand in the Hauraki-Waikato electorate.

"I'm not here to judge him, he may feel that he needed to judge me, but I'm not here to judge him. I think people will interpret his comments in such a way that they're quite out of character with generally what the kingitanga stands for and represents," she said.

"For the time I've been a member of parliament I've never had a formal endorsement from the kingitanga so it's definitely a new approach. That's mainly because the politics of the kingitanga has been above party politics and it's had an agenda that stands on its own merits.

"It's not really been centralised, if you like, in any one political party - not as long as I've been in parliament and I've certainly never received any formal endorsement from the kingitanga of my candidacy and membership in previous years."

FAIRFAX NZ Maori Party president Tukoroirangi Morgan, who is also an advisor to the King, is said to be behind Tuheitia's political moves.

She says she never expected it either.

"I think tribal members will be quite concerned now about what does this mean. Are the tribal politics and party politics so inextricably linked that people can't separate them? I think there will be some concern about this."

Mahuta isn't standing on the Labour Party list because she wants a "clean, straight race" in the seat and "if people want me they'll choose me".

As to how much influence Tuheitia has, she says "time will tell".

"When people go to the polling booth and what they decide to do and how they place their vote is between them and the ballot box."

"He's got his own opinion...one individual can't affect that outcome - a million can though - and I'm focussed on the million."

Mahuta was recently appointed to lead Ngati Maniapoto's treaty settlement negotiations but she says that role complements her position as an MP and wouldn't be seen as a reason not to vote for her.

And if she isn't re-elected Mahuta says she doesn't think her relationship with kingitanga will be damaged.

"You can't cut people off from their whakapapa and their connection to their iwi."

Mahuta has no plans to talk to Tuheitia about his comments and says she's not interested in why he made them.

"He's chosen his forum to make a statement. I'm not going to get involved in why he said that, what's motivating him or who is behind that," she said.

After Tuheitia turned his back on Labour and pledged his allegiance to the Maori Party at last year's celebrations of the King's coronation in Ngaruawahia, speculation was rife Papa would stand for the Maori Party.

Last month a deal was struck between the Maori Party and Mana that would see a clear run for Hone Harawira in Te Tai Tokerau in exchange for Mana staying out of the other Maori seats.

Maori Party president Tuku Morgan said Papa, who is the chairman of the Waikato Tainui tribal executive, was the right person for the job and would now go through the process of becoming the party's official candidate.

"King Tuheitia is a game-changer, no doubt. Whoever he endorses makes the seat winnable for the Maori Party."

Morgan said it was Tuheitia's right to endorse a candidate and while it had never been done before, Kingitanga had always been political.

Labour's Tamaki Makaurau MP Peeni Henare said any impact on Mahuta's "mana" was for the Hauraki-Waikato electorate to decide, not the King.

Henare, who continues to have his appointment as an advisor to the King delayed, said the "house of Kingitanga and whoever holds that mantle" should stay separate from politics.

"The position of the person who holds the mantle is one not of common touch, it should remain tapu. So I agree with Nanaia's sentiment that the Kingitanga has entered into grey territory by nailing its flag to a mast and it's done that with the Maori Party," he said.