The group has six months' steady practise behind it, after winning the Aotea Region competition in 2017. It includes three of Manuel's seven children.
Two of his eldest children, Justin-Leigh and Chaeli, are among its tutors, along with Kania Martin and Taria Ngawhika.
The group's 25-minute performance has been carefully planned, Manuel said. Because the school is Catholic it includes a passage from the Bible set to music. Its entrance makes reference to a long line of Māori prophets from this western part of New Zealand.
They include Te Ua Haumene, Tohu Kakahi, Te Whiti, Te Mareikura, T. W. Ratana and Mere Rikiriki - who had links to Manawatū and Rangitīkei. A traditonal waiata, composed by the late Morvin Simon, speaks of the importance of the Whanganui River and why it deserves recognition as a legal entity.
One piece honours people who have died recently; teacher and broadcaster Kōtuku Tibble, Whanganui principal Stuart Kawau and cervical smear campaigner Talei Morrison. The haka, composed by Tema Hemi, is about youth suicide and symptoms such as depression.
"It's a disease that's particularly affecting our youth. We are encouraging tāne Māori to open up and kōrero about what's going on inside of them emotionally."
For Manuel, the week of the competition will be his last at Cullinane College. He's leaving to become assistant principal at Whangarei Boys' College. It is a good moment to leave, he said.
"I'm happy with the way the school is now, and we have finally got a wharenui."