Rehua was the overall Senior winner of the Te Arawa regional competition earlier this year. His winning speech was "Ka kuku te kereru, ka auau te kuri, kei te korero Pakeha tonu te iwi Maori - the kereru makes its sound, the dog still barks but the Maori people are still speaking English".
He said he travelled to New Plymouth to put his thoughts before a bigger audience.
"And I guess I did that." Rehua said he received awesome feedback following his speech including praise from a number of teachers at the competition who told him they agreed with his korero.
"Their comments kind of made it clear to me my message had travelled."
A video of Rehua making his speech in New Plymouth was posted to the Rotorua Boys' High School Facebook page on Thursday night and had been viewed more than 16,000 times before his first placing was announced.
#WATCH Head Prefect, Rehua Selwyn at Ngā Manu Kōrero 2017 today.
Posted by Rotorua Boys' High School on Wednesday, 20 September 2017
Also taking the stage was Whatukura Mohi who placed second in the junior Maori section of the event. Whatukura spoke on the topic "He manu hou ahau, he pi ka rere - about a new bird going into the world and gathering information and knowledge."
Manaia Lewis-Wano from Rotorua Girls' High spoke in the junior English section and Shanayla Barrett from Western Heights High School represented her school in the senior English section.