Tinirau said the relatively late change left them looking around the community for sponsorship but he said the community really got behind the event.
"The local community, as well as other organisations within the wider zone, have contributed to it and they've all risen to the challenge," he said.
The event is also closed, with no public sales of tickets.
Tickets were instead sold by the competing rōpū for each region.
"There haven't been many rōpū that haven't been able to sell their tickets, and all those sales contribute to offsetting the costs as well," he said.
Deputy principal at Whanganui City College Valerie Rooderkirk said hosting the event meant a lot for the school.
She said Māori performing arts had become a large part of the school's curriculum as it is one of the schools piloting the NCEA Te Ao Haka programme, which will give students a learning pathway through to university entrance with Māori performing arts.
"It's an amazing achievement because it's taken such a long time to get [from] that point where Māori performing arts wasn't really recognised correctly within the curriculum," Tinirau said on the programme.
She also hoped the event will be an inspiration to the school's own kapa haka group, who narrowly missed out on qualification for the finals last year.
"Hopefully this will inspire them for next year's qualifying," she said.
Roodekirk said the rōpū will be arriving in Whanganui from Tuesday and were staying in local marae and the Aramoho motor camp before Friday's contest.
"It's like any sports tournament, they've got to get here and get set up and warmed up and in the zone, cause it's huge," Roodekirk said.
All eight groups will take part in a pōwhiri for the event at 11am on Thursday, with all groups also getting a 15-minute stage check before the actual competition kicks off from 8.30am on Friday. All performances should be done by 3pm.
The competition will be broadcast on Whakaata Māori in pool order from 9am on September 20, with the top nine groups announced on September 22. Finals day and the prizegiving airs on September 23.