The current record is 4028 people, set in France 10 years ago.
In 2016, 6000 people attempted to break that record in Masterton and then in 2017, an estimated 7700 people in Rotorua showed up for a mass haka as the British and Irish Lions prepared to play the Māori All Blacks. Neither of those attempts were officially recognised.
Dame Hinewehi Mohi is championing the world record attempt as part of the 20th anniversary of the Raukatauri Music Therapy Trust, named after her daughter Hineraukatauri, who has severe cerebral palsy.
The event, which starts at 4.30pm, features pre-record attempt entertainment from Kiwi music stars including Six60, Alien Weaponry, Che Fu, Rob Ruha and the Topp Twins.
Dame Hinewehi told Mihi Forbes on RNZ's Saturday Morning programme it was time to bring the record home.
"It is a cultural icon that is quintessentially ours, from Aotearoa, and represents us, and the world knows it, and the world loves it.... We need to get that record back now, this project has consumed me and everyone else involved for the past five months. We felt so passionate about this and saw it as an opportunity to really bring the nation together."
Ten thousand participant tickets were available, with additional tickets offered for people wanting to watch in the stands.
"Come along and buy a ticket at the box office. You can watch from the stands, or haka from the stands," Dame Hinewehi said.
She pointed out that when the All Blacks performed the haka during an international match, people rarely joined in.
"Usually the practice when a haka is performed, is that everyone joins in. But for that particular situation... people don't... so let's change that.
"We feel empowered by learning. Maybe if we're a bit rusty with the actions or the words, or we don't know it at all, and we're taking the time to learn for the very first time, it will be something that you will never forget."
Forbes asked if people needed to be "at Matatini standard, or rejects like me are allowed to" participate?
"Even those who are physically challenged, unable to fully participate but give it all their heart. Everything about it is accessibility... for those in the third row, fourth row, or supporters club for the kapa haka of their kids at school, it's all about coming and joining in."
Proceeds from today's event will help provide ongoing support for the Raukatauri Music Therapy Trust.
Dame Hinewehi said the trust was inspired by her daughter.
"Everything started for us when Hineraukatauri was just a little baby and she responded to music.
"Babies do respond to sound and the things around them, and the natural connection to music is often what you see when a toddler is jiggling along to some kind of rhythm they connect with - this all starts in utero.
"When the māmā is hapū and there is the heartbeat and the rhythm of all that is around the mother, so that's where our groove comes along and some kind of natural connection to sound and rhythm and melody."
Participants will perform the well known Ngāti Toa haka Ka Mate, which is often performed by the All Blacks.
A mass contingent of Ngāti Toa descendants from across the country will come together in Auckland to take part and provide guidance, before, during and after the haka.
Performances from artists supporting the event begin at 4.30pm. The haka attempt set to take place in the evening and will be live-streamed by Whakaata Māori.
