Ka Hao is a 24-member youth choir drawn from all around the Te Tairāwhiti, Gisborne area.
Here is a wonderful a wonderful article about Ka Hao by Ella Karalus-Gannaz in NZ MUsician. In the article there's link to an interview with muscian Rob Ruha of interest. I understand nothing in the Maori language so looking up Io Matua Kore I was delighted to discover that a simple: "Oh it's a song about God" simply doesn't make the cut. The place of this performace is the historic St. Mary's Church wihich is also a memorial to the Ngāti Porou soldiers who who died in World War I.
Songs are sneaky things*.