Ratana followers have been welcomed onto the church's marae near Whanganui at the start of annual celebrations.
On a warm sunny day, more than 300 people have been received at Ratana on Wednesday during three powhiri.
People are gathering to celebrate the birth of the church's founder Tahupotiki Wiremu Ratana.
Politicians to arrive Wednesday, included Maori Party co-leader Pita Sharples and MP Te Ureroa Flavell who came onto Ratana Pa with an indigenous Japanese delegation.
The Ainu people, from Hokkaido, have historical links with Ratana and Mr Flavell said the visit is an opportunity to re-establish that relationship.
A Ratana Church spokesperson Ruia Aperahama said the Ainu visit is important because there are lessons and models they can use to help strengthen their cultural identity as tangata whenua of northern Japan.
Mana Party leader Hone Harawira is also at the pa with a delegation from Te Tai Tokerau.
On Thursday, the main political day at the pa, Prime Minister John Key, government ministers and Labour and Greens MPs give speeches.