Professor Mātāmua has dedicated much of his life to the revitilisation and resurgence of Matariki and has written widely about Matariki.
He is regarded as one of the country's foremost Māori scholars for his contribution to Māori astronomy, star lore and Māori culture was made an Officer of the New Zealand Order of Merit in 2022.
Professor Mātāmua said he was not expecting to get the New Zealand of the Year award and so did not have anything prepared.
"I was in the same category with Ruby Tui, The Topp Twins and John Kirwin and you know these are icons within the nation and I was so privileged just to be amongst them. So I didn't have a single word prepared - I was really looking forward to celebrating their win.
"And my name got called out and I was shocked."
Professor Mātāmua said Aotearoa was going in the right direction as a nation.
"I think every year as a nation we will stop to celebrate mātauranga Māori, we will stop to come together and use Matariki as a pillar for the ongoing forging of our national identity and we will celebrate something that is underpinned by the values of remembering those who have gone before us and their legacy they've left behind."
Matariki allowed New Zealanders to celebrate "who we are with all our diversity" with an eye to the future in terms of who we want to be, he said.
Professor Mātāmua said his family were very emotional when he received the award and he had to tell his mum to stop crying but "it was awesome to have them there".
He said he believed he won the award due to his work on Matariki which was widely taken on board by a large section of the nation.
"You know Matariki is just such a wonderful kind of symbol for unity and collectivity because it's beyond politics or beyond even a nation or a single culture, you know those stars were universally recognised across the world from Europe to Asia to Africa, North and South America, right across the Pacific and here in Aotearoa."
The stars were understood to be marks of "season, of celebration, of harvest, of coming together", he said.
In Aotearoa the stars were used to remember those who we had lost in the past year, to celebrate who we are and then to look to the future to celebrate who we want to be, he said.
It was "really amazing" to be acknowledged for that body of work, he said.
