The founder and former co-leader of Te Pāti Māori suffered a stroke earlier this week and was said not to have long left.
Te Ranga Tupua said in a post on Facebook that she had passed away early on Friday morning.
"A mother of six; grandmother; and great-grandmother of over 80 mokopuna, Kahurangi (Dame) Tariana will be remembered for spearheading a movement of transformation inspired by her belief in whānau being able to define their own solutions," the post said.
Her introduction of Whānau Ora in 2002 was instrumental in changing how the state interacted with Māori, it said.
"Kahurangi Tariana championed the drive for self-determination; becoming co-leader of the Māori Party in 2004 after she famously 'crossed the floor' to vote against the Foreshore and Seabed Bill."
Dame Tariana served as a member of parliament for 18 years, initially as a list MP for Labour, then in the Te Tai Hauāuru electorate.
She left Labour in 2004 and returned to parliament after winning a by-election for Te Pāti Māori.
"The loss of her beloved husband, George, in April 2019 took a significant toll on Dame Tariana, as has her declining health over the last two years.
"It was her heartfelt wish to return home to lie in the house of Rangitāhuahua; her last days surrounded with the laughter of mokopuna, the waiata of her whānau; the karakia and kōrero that had always given her comfort."
Friday and Saturday would be a time for her whānau and iwi to gather at Putiki Marae and in Whangaehu.
Others were welcome to visit and pay their respects on Sunday and Monday.
Dame Tariana's nehu would be held on Tuesday 7 January.
