Te Reanga Morehu o Ratana was the first to perform at the festival.
Jamie Nepia had tears in his eyes when the group took to the stage.
He has travelled from Ratana to support them.
"Te Matatini Ki Te Ao is important in terms of keeping our culture and also it's a chance for all iwi denominations to come together as one to showcase our maoritanga and our maoriness."
Arama Ehau has come from Rotorua with his family to be at the event.
He said he was most looking forward to the entrances of each performance.
"To us kapa haka is probably the greatest expression in Maoridom at present."
The Ministry for Culture and Heritage expects up to 65,000 tickets to be sold over the four-day festival.
Chief executive Bernadette Cavanagh said kapa haka made a significant contribution to New Zealand's national identity and played an important role in Māori language renewal throughout the country.
"Kapa haka brings our nation's stories to life."
The theme of the 2019 festival is Te Matatini ki te Ao, which means Te Matatini to the world.
It's meant to promote the status of Te Matatini as a world-class festival and a global stage for Māori performance excellence.
The festival would excite, inspire and challenge, Minister for Māori Development Nanaia Mahuta said.
"It is a platform for the revitalisation of te reo Māori, and a path to improve wellbeing, re-connect with hapū and iwi, and creates a space for young Māori to emerge as leaders."
At Waitangi Park yesterday, thousands attended a powhiri to open the festival.
Gates open to Westpac Stadium at 7am this morning.
But it's not all about what's happening on the stage, Te Puni Kōkiri chief executive Michelle Hippolite said.
"It's the whānau that turn up in droves to support their loved ones, immerse themselves in a te reo Māori environment and connect with others they may not have seen for ages."
Teams and their supporters are staying in a range of accommodation including hotels, motels and marae, in the Wellington region as far as the Hutt Valley and Waikanae.
Wellington City Council has put a spin on the festival by installing special "haka lantern" pedestrian crossing lights.
The lanterns see the iconic walking image at pedestrian crossings changed to a wahine and a warrior demonstrating a haka.
The council has asked commuters to be patient and expect some delays during the event.
There will also be no public parking available at the stadium from February 21 to 24.
However, the council's Clifton Terrace carpark will be open, along with the Ballantrae Pl carpark.
Performers and volunteers at Te Matatini will be able to travel to and from the competition, and around the region, for free on all Metlink train and bus services.
