Prime Minister Jacinda Ardern will be welcomed at Rātana this morning for the church's annual festivities.
The pilgrimage of politicians to Rātana Pā traditionally marks the start of the political calendar and has special significance this year as the centennial event.
The celebrations, near Whanganui, mark the birthday of the church's founder, Tahupōtiki Wiremu Rātana.
This will be Ms Ardern's first visit to Rātana as Prime Minister and Labour leader. Along with MPs from Labour, New Zealand First and the Green Party, she is expected to arrive about 11am.
Ms Ardern said she was looking forward to the event, and acknowledged the church may have certain expectations now Labour was in power.
"I welcome that. Expectations are what keep driving you harder."
Her speech would raise practical ways the government and church could work together on their shared priorities, Ms Ardern said.
National leader Bill English and his team would be welcomed in the early afternoon. He said he expected the reception to be "respectful and warm" as usual.
"I'm looking forward to the opportunity [to attend]. I've got to know a number of them over the years from attending regularly."
Mr English said he expected the tone of the event to be different given the new government and Rātana's traditional ties to Labour, but had a warning for those attending.
"What Māori have to watch out for is the urge of Labour to control Māori institutions.
"Labour have never been happy with the degree of independence or rangatiratanga that iwi have shown."
Māori leaders - including the Māori King Tuheitia and representatives of the Māori Party - were invited onto the marae on Tuesday.
Last year, a political squabble stole the spotlight as then-TOP leader Gareth Morgan insulted New Zealand First's Winston Peters, describing him as an "Uncle Tom".
Māori Party co-leader Te Ururoa Flavell also challenged the church's historical political tie with Labour, calling for a new unified Māori movement.
In 2016, the event was coloured by protest at the Trans Pacific Partnership.
The year before, government and opposition MPs walked on to the Pā together for the first time after the schedule ran late.
Green Party co-leader at the time Metiria Turei used the event to attack then-Prime Minister John Key, who was absent due to being overseas.
The political history of Rātana goes back to the late 1920s, when T W Rātana announced that members of the church would stand in the then-four Māori seats.
They announced a formal alliance with the Labour Party in 1936.