The British government has expressed regret for the killing of Māori people in New Zealand after the explorer Captain James Cook’s arrival in the country in 1769.

But the statement from the British high commissioner to New Zealand, Laura Clarke, to local tribes – known as iwi – was made in private and stopped short of an apology.

The meetings with iwi in the city of Gisborne, on the east coast of New Zealand’s North Island, came days before a government-funded commemoration of Cook’s landing there, including a replica of his sailing ship along with a flotilla of other vessels.

The anniversary events have been decried by some Māori groups as insensitive and protests are expected at this weekend’s events.

When the British explorer arrived on the east side of the Turanganui River, near present-day Gisborne, the first encounter between his men and the Māori inhabitants was disastrous, according to an official New Zealand history site, with a leader from the Ngāti Oneone group immediately shot and killed. It seemed likely the local people were undertaking a ceremonial challenge, which the Europeans misunderstood, the site said.

At least eight other Māori are believed to have been killed. The British high commission said in its statement that Cook had written of his regret over the deaths in his diary.

Speaking to the Guardian from Gisborne, Clarke described the meeting as “emotional” on all sides, with tears shed by all.

Iwi groups have been in negotiations with Clarke on reconciliation for more than nine months, and the event marks a new beginning for relations between the British government and Māori people, the high commissioner said.

“What we did today, really acknowledged, perhaps properly for the first time, that nine people and nine ancestors were killed in those first meetings between Captain Cook and New Zealand Māori, and that is not how any of us would have wanted those first encounters to have happened,” she said.

“So it’s a really significant part of our shared history, and a sad one, so it felt really important to acknowledge that pain of those first encounters. Acknowledge that the pain doesn’t diminish over time, and if you do that, if you look back to address the wrongs of the past, it equips you better I think to look to the future and build a partnership.”

Clarke said her team had been “really focused” on acknowledging past wrongs between Cook and Māori people and there were as yet no plans to make further efforts at formal reconciliations with iwi groups around the country.

“That meeting of Cook and Māori marks the beginning of modern Aotearoa [the Māori name for the country] New Zealand so it was really a important first encounter and it went tragically wrong and that’s what we’re trying to recognise. So it’s very focused on this one historic incident and very focused on this relationship between the UK and the descendants of those who were killed,” she said.

Iwi groups applauded Clarke’s diplomatic efforts and described her public expressions of sympathy and regret as sincere and profound, saying they were enough for now to begin the healing process.

Only a small handful of official statements have been made by the UK government about its actions overseas during the colonial period. In 2013, it expressed regret and announced compensation payments for those tortured in prison during Kenya’s Mau Mau insurgency.

And earlier this year, on the 100th anniversary of the Amritsar massacre in India, in which British troops fired on crowds, killing 379 according to official figures, the government expressed “deep regret” – but again stopped short of an official apology.

Clarke was appointed to Wellington in January 2018 and has since spoken admiringly of the push towards “righting past wrongs” in the treatment of Māori by New Zealand governments and the UK.

She is learning te reo Māori (the Māori language) and last year the high commission recruited its first adviser on Māori affairs.

Meng Foon, New Zealand’s race relations commissioner and a former mayor of Gisborne, told Radio New Zealand the British statement was significant and he hoped it would help iwi move forward.

But Tina Ngata, a Māori rights advocate who has been leading the opposition to the commemorations of Cook’s arrival, said words were not enough without change.

Last month, she told Radio New Zealand that Cook was “a murderer, he was an invader [and] he was a vanguard for British imperial expansion”.

The New Zealand prime minister, Jacinda Ardern, will visit Gisborne at the weekend for the official commemorations but will not participate in Wednesday’s expression of regret.