King Tuheitia has taken a significant step in this year's election by endorsing Maori Party candidate Rahui Papa in the Hauraki Waikato seat now held by the king's cousin, Labour MP Nanaia Mahuta.
Papa chairs Te Arataura, the executive arm of Waikato-Tainui and is close to the king.
He has been widely tipped as the Maori Party candidate and is expected to be officially selected next week.
Mahuta has been an MP since 1996 and has held the seat since 1999, although last year she considered retiring at this year's election.
The king made his comments yesterday at a private meeting at Parawera Marae, south of Hamilton, and he criticised Labour's treatment of Mahuta.
"She has gone right to the back, the back bench. To me she has got no mana now," TV1 reported him as saying.
Maori Party president Tukoroirangi Morgan who is a close adviser of the king, was present and described the endorsement as "a game changer".
Papa said the endorsement was humbling and overwhelming.
The Maori Party holds only Waiariki, held by co-leader Te Ururoa Flavell, out of the seven Maori seats.
It has entered a deal with Hone Harawira's Mana Movement in a bid to regain more seats. It will stand aside in Te Tai Tokerau for Harawira and his party will not stand in any of the other six Maori electorates.
Mahuta's majority in the 2014 election of 7695 is more than the combined vote of the Maori Party and Mana candidates.
Her late father, Sir Robert Mahuta, was the adopted old brother of the king's mother, Dame Te Atairaangikahu.
The king's endorsement follows criticism he made in August last year of Labour and New Zealand First during a speech at annual coronation celebrations at Turangawaewae.
"It really hurt me when the leader of the Labour Party says 'I'll never work with that Maori Party.' I'm not voting for them any more."
On New Zealand First leader Winston Peters, the king said then: "He might be a Maori but he doesn't act like one."
Peters said at the time that the king was being used by Morgan, a former New Zealand First MP, to get involved in domestic politics and he should remain neutral.
"There is no way his predecessor, the Maori Queen, would ever have done that."
Nanaia Mahuta, a former cabinet minister and former front bencher, is ranked at No 11 in the Labour caucus. She does not sit on the front bench although leader Andrew Little chooses to refer to his top 12 MPs as "front bench" MPs.