Gisborne iwi are set to receive a message this afternoon from the British High Commissioner for the Māori killed when James Cook arrived in 1769.
The British High Commissioner is taking part in one of her first of two ceremonies in an expression of regret to iwi in Gisborne - in what is understood to be a first in New Zealand.
British High Commissioner Laura Clarke has been working closely with leaders of Gisborne iwi Rongowhakaata, Ngāi Tāmanuhiri, Te Aitanga a-Māhaki, Ngāti Oneone for many months to prepare for this meeting.
This afternoon Ms Clarke will express regret on behalf of the Government of the United Kingdom of Great Britain and Northern Ireland, for the deaths of nine Māori killed during the first encounters with the crew of Captain James Cook's Endeavour.
She was welcomed on to Te Poho o Rawiri Marae this morning and will attend another ceremony this afternoon.
The expression of regret and ceremonies are in response to Tūranganui-a-Kiwa iwi wanting their history to be heard and acknowledged.
The British High Commission isn't calling it an apology but instead an expression of regret on behalf of its government.
In a series of two events, she will address Ngāti Oneone at Te Poho o Rawiri Marae and will then go to Whakatō Marae in Manutūkē for another ceremony to address, Ngāi Tāmanuhiri, Rongowhakaata and Te Aitanga a Māhaki.
Ms Clarke will acknowledge the pain of those first encounters, acknowledge the pain does not diminish over time and extend her sympathy to the descendants of those killed.
The Commission hopes that it is the beginning of a longer process, and forward-looking relationship between these iwi and the United Kingdom.
Descendants will also have an opportunity to meet with the Commissioner tomorrow to have further discussions about the expression of regret.
The British High Commissioner does not represent Queen Elizabeth II, who is represented by the Governor-General.
The role of the High Commissioner is to lead the United Kingdom's diplomatic relationship with New Zealand.
In a statement posted on its Facebook page the Rongowhakaata Iwi Trust says the ceremony is to acknowledge the hara or atrocities committed 250 years ago.
A number of Māori warriors including at least one chief were killed by Cook's men during their first meetings in early October.
Commemorations marking the arrival start this weekend in Gisborne and protests are expected.
The trust did not respond to a request for comment.
But Gisborne's outgoing mayor and the new Race Relations Commissioner, Meng Foon, said an official apology from the British government was very significant and he hoped it would help heal the relationship.
"It's a significant day today," he told Morning Report.
"This is a face-to-face private meeting between the British High Commissioner, the Crown and the iwi that were affected.
"I hope that the apology or message will acknowledge the murder of nine Māori from Tūranganui-a-Kiwa, and I hope they both can move forward and tell our history - for the rest of New Zealanders, but more particularly here in Tūranganui-a-Kiwa."
Indigenous rights advocate Tina Ngata, who has been leading the opposition to Tuia 250, told Morning Report it would take action behind the words to make a difference.
"In and of it itself, for the broad experience of what's happened, I don't think words are enough. It needs to be accompanied with change, with some clear actions, and a pathway. And the pathway should always be determined and defined by those who have borne the brunt of the experience."
She said there should be a review on Tuia 250.
"It's up to iwi and hapū to discuss what those reconciliation pathways should look like. This has had an enduring impact upon all of Māoridom, so the most important thing is it's defined by the people, not defined by the government and that it's accompanied with clear action."
Minister for Crown Māori Relations Kelvin Davis said: "We've said this is nothing to do with us. This is entirely an issue between the High Commission and the Tūranga iwi. And what the High Commission has to say to Tūranga iwi is entirely up to them."
Mr Davis and Prime Minister Jacinda Ardern are expected to visit Tūranganui-a-Kiwa or Poverty Bay this weekend.