The prime minister travelled to the King Country settlement of Te Kuiti to issue the apology, the first she has delivered personally as part of reconciliation and treaty settlement efforts.

After 30 years of negotiations with the Ngati Maniapoto tribe, the government agreed to $NZ165 million ($A155 million) of financial and commercial redress, and the return 36 sites of cultural significance to Maori.

"This is a momentous occasion for both Maniapoto and the Crown and marks the beginning of a renewed relationship," Ms Ardern said, reading the formal apology in both English and the Maori language at a ceremony attended by 3000 people on Sunday.

Historic wrongdoing dates back to the mid 19th century, when the NZ colonial government fought with and alongside Maori over land.

"The Crown profoundly regrets its horrific and needless acts of war and raupatu (land confiscation) which have caused you and your hapu (tribe) inter-generational suffering," Ms Ardern said.

"Instead of respecting your mana whakahaere (authority), the Crown killed and injured your people, and pillaged your land and property."

In the late 19th century, locals were pressured to open up to European settlement and run a railroad through Maniapoto territory, which led to aggressive land acquisitions from Maori hands.

Bella Takiari-Brame, who will administer a trust arising from the settlement, said the impact was still felt in 2022.

"We lost our land. We lost our language. We've lost our identity and it created inequities and disparities since for our people," she told TVNZ.

"We have clear aspirations to ensure we return back to who were were. We were entrepreneurs. We were exporting overseas. We were thriving."

Ms Ardern acknowledged the government of the day was responsible for "devastating long-term prejudice".

"As a result, your hapu and whanau (families) have faced significant socio-economic deprivation and lived in worse conditions than non-Maori. You were prevented from reaching your full social and economic potential and had to fight to maintain your Maniapoto identity and language."

The Treaty of Waitangi, signed in 1840 by representatives of the British Crown and hundreds of Maori chiefs, is considered NZ's foundational document.

Misunderstandings over its meaning and translation continue to hound reconciliation efforts and full participation of Maori in modern life.

Since 1975 - when the Waitangi Tribunal was founded - governments of all political persuasions have pursued treaty settlements as a means of rectifying those wrongdoings, signing dozens of settlements and apologies.

Treaty Negotiations Minister Andrew Little said he wanted Sunday's apology to "lay the groundwork for a new partnership to provide for the future wellbeing and prosperity of Maniapoto".

"When Maniapoto rangatira (Maori chiefs) signed the Treaty in 1840, they expected to build a partnership with the Crown," he said.

"For more than a century after this, the Crown repeatedly broke the promises it made leading to devastating loss of life and land, and social and economic deprivation."

The apology followed a two-day celebration of a new "whare tupuna" (ancestral house) built in Te Kuiti.

Australian Associated Press