Prime Minister John Key said Dr Walker was a leader by example and would be missed by many across New Zealand.
"He was not only an insightful commentator on important historical and contemporary issues, but was a tireless and passionate advocate for Maori," Mr Key said.
"I always enjoyed seeing Dr Walker, and felt privileged when he sent me copies of his work."
He said his thoughts were with Dr Walker's whanau and friends as they mourned his passing.
He pointed to Dr Walker's contribution to New Zealand history through the books he had authored and his contribution to the development of Te Ara - the Encyclopedia of New Zealand, as well as his role on the Waitangi Tribunal since 2003.
Dr Walker's service to Maori was recognised in 2001 when he became a Distinguished Companion on the New Zealand Order of Merit.
Maori Party co-leader Te Ururoa Flavell has paid tribute to his former lecturer, Dr Walker, saying he had a major impact on the course of Mr Flavell's life and Maori rights.
Mr Flavell said he was saddened to hear Dr Walker had passed away, saying he had a huge influence on thousands of students at Auckland University in the 1960s and 1970s, including Mr Flavell himself.
"I owe a huge debt of gratitude to Ranginui for the impact he's had on the course of my life. He was one of the few commentators of his time to put the injustices Maori had suffered in a way that both Maori and Pakeha could understand."
He said Mr Walker was a key figure on the Auckland Maori Council until 1990 and supporter of activist group Nga Tama Toa in the 1970s. One of the academic's greatest legacies was a prolific written record of contemporary Maori history.
"He was fearless and controversial. His messages ruffled feathers but few could argue with his rigorous research and knowledge."
Labour's Maori Affairs spokesman Kelvin Davis said Dr Walker was a "towering voice" who fought tirelessly for Maori for decades.
"His contribution to academia, education and politics has been without peer and he stands as a truly great New Zealander. In almost all debates on the future of Maori, he has been a towering voice.
"He was a leader, a thinker and a fighter. He was also humble in his service. That's how he should be remembered."
Green Party co-leader Metiria Turei said Dr Walker was held in "huge esteem" throughout New Zealand and by many in the party.
"I have been on many panels with Ranginui and he has always been open to a fiery debate," she said. "He was incredibly well informed, highly opinionated, and always willing to have an open conversation.
"As a Maori activist lawyer, then politician, I have always had a lot to learn from listening and watching kaumatua like Ranginui Walker. The Green Party and I will miss him.
"Dr Walker wrote that the quest for a fair partnership under the Treaty was 'struggle without end'. Despite his passing, his work in helping to bring new generations together in a better understanding of that partnership endures."
The leaders of Ngapuhi hapu say the death of Dr Walker will be mourned by the iwi which loved and respected him.
Dr Walker has been a member of the Waitangi Tribunal since 2003 and the co-chair of Ngapuhi's Te Kotahitanga group Pita Tipene said he would be missed in the current hearings in the Ngapuhi - Te Paparahi o Te Raki Inquiry.
"His presence and thirst for understanding Ngapuhi history, understanding our past grievances will be sorely missed. We are saddened by the loss of this esteemed academic, an inspirational leader who the people of Ngapuhi loved and respected.
"A giant totara has fallen in the forest and the reverberations will be felt by all."
Mr Tipene said Dr Walker had also been instrumental in a Waitangi Tribunal last year which found Ngapuhi had not ceded sovereignty when signing the Treaty.
READ MORE: In his own words: The Struggle Without End
Labour MP Grant Robertson tweeted: "Deeply saddened to hear of the passing of Ranginui Walker. A dignified, humble and committed scholar and a leader. Moe mai ra e rangitira."
Singer and documentary maker Moana Maniapoto posted on Twitter: "Incredible legacy & staunch to the end. Ka whawhai tonu ake ake. Ka Nui Te Aroha."
She added: "Spoke to him recently. Clear, consistent & utterly committed. Never wavered. Intellectual great, true warrior."
Media commentator Russell Brown tweeted: "I'm of a Pakeha generation for whom Dr Walker *was* our view of Te Ao Māori. I feel shattered by his passing."
Academic Dr Paul Moon Dr Walker was an extraordinarily productive researcher and writer, who kept giving seminars and publishing books.
Dr Walker was born into a farming family belonging to the Whakatohea iwi of Opotiki. He was educated at St Peters Maori College, was a primary school teacher for 10 years and was a lecturer at Auckland University from 1967 for five years.
His academic career saw him delving into anthropology, education, and Maori studies.
In the 1970s, he was a member of the Maori activist group Ngā Tama Toa which promoted Maori rights and fought against racial discrimination.
He eventually became a full professor and head of the University's department of Maori studies and served at its first Maori pro-vice chancellor. Dr Walker retired from the university in 1998.
He was one of 10 people being considered for this year's Kiwibank New Zealander of the Year award, for his services to Maori.
Dr Walker was married to Deirdre and they had three children.
