The Government and Air New Zealand have apologised to the families of the 257 people who died in the 1979 Erebus disaster.
Family members have gathered at Government House in Auckland to mark 40 years since the tragedy.
Prime Minister Jacinda Ardern said the way the report was handled was wrong, and the wrongs need to be acknowledged.
She said after 40 years, it's time to say she's sorry, on behalf of the Government. Neither the government or Air New Zealand had made a full apology before.
Listen to NZ Herald's podcast on the Erebus disaster, here.
Ardern said the time has come to end "piecemeal" responses and that failures to acknowledge past wrongs had made the families' grief more difficult.
"After 40 years, on behalf of today's government, the time has come to apologise for the actions of an airline then in full state ownership which ultimately caused the loss of the aircraft and the loss of those you loved," she said.
"This apology is whole hearted and wide reaching. We will never know your grief, but I know the time has come to say I am sorry."
Air New Zealand chair Dame Therese Walsh says the airline apologises for failing its duty of care for passengers and staff.
Walsh says she apologises to the families, who were poorly treated by Air New Zealand staff.
Also present at the gathering were members of the recovery team tasked with the job of recovering bodies of the dead.
• Air NZ's missing flight path evidence confirms 'orchestrated litany of lies' over Erebus - Judge Gary Harrison
• Erebus Flight 901: Litany of Lies. Episode 9: The five words that sank Justice Peter Mahon
• Erebus Flight 901: Litany of Lies. Episode 8: Judge - 'There had to be some sort of cover-up'
• Erebus Flight 901: Litany of Lies. Episode 7: 'Whiteout - that's what killed them'
On the morning of November 28, 1979, Air New Zealand flight TE901 left Auckland for a sightseeing flight to Antarctica. At 12.49pm the aircraft crashed into Mt Erebus in Antarctica, killing all 237 passengers and 20 crew.
Erebus remains the worst peacetime accident in New Zealand's history, the scale of loss shocked the nation. The plane was lost from the fleet of the national carrier; Air New Zealand was in full state ownership at that time.
President of the New Zealand Air Line Pilots' Association Andrew Ridling said the apology was a game changer.
"The pilots on board the aircraft that day were subject to unfair conjecture and blame that affected their professional reputations," Captain Ridling said.
"We have waited a very long time to see that put right."
He said it was very important to the association and the families to hear the Prime Minister say the pilots were not responsible for the tragedy.
"It's impossible to underestimate the effect of just a few words," Ridling said.
"For New Zealanders, the word Erebus is not just a mountain on a cold distant continent. It is now a by-word for a dark time we hope never to experience again."
Earlier in the afternoon, the E tū union held a service at the Erebus Crew Memorial Gardens at Auckland Airport.
"Erebus changed a nation," says E tū's Head of Aviation, Savage.
"257 people from New Zealand and around the world died. This was one of our worst industrial accidents, a day when 20 aviation workers lost their lives.
"It changed the way the whole world thought about aviation safety and about our shared responsibilities to put safety first," he says.
"We invite all New Zealanders wherever they are in the world to pause for a minute and reflect on the event and the importance of safety at work and the responsibility we all have to look out for one another."
PM's full speech to Erebus families
E aku manukura, tēnā koutou. He kupu whakamahara tēnei i te aituā nui i Te Tiri o Te Moana, i Erebus I runga i tētahi maunga tiketike i riro atu rā tētahi hunga i arohanuitia E murimuri aroha tonu ana ki a rātou. Kua titia rātou ki te manawa, mō te āke tonu.
Ko te pō ki a rātou, nau mai te ao ki a tātou, tēnā tātou.
Greetings distinguished guests. In remembrance of the tragic events of Erebus. On a high mountain, those who were loved, were lost. We continue to grieve for them. They are etched forever in our hearts. The place of the departed is for them; for us, the world of light – greetings to us all.
My very warm greetings to all of you gathered here today:
Your Excellency, to whom I give my very grateful thanks for hosting this event; families of the Erebus victims; members of the Diplomatic Corps, representing families from other nations; members of Operation Overdue; Hon Nikki Kaye, representing the Leader of the Opposition; Mayor Goff; representatives of the New Zealand Police and Defence Force; Dame Therese Walsh and other representatives of Air New Zealand; representatives of Ngāti Whātua Ōrākei; Rev Dr Richard Waugh; supporters and friends.
It is twelve months since I last met with many of you, and I feel privileged to be in your presence again on an occasion that is so deeply personal for so many.
In a year that has seen new tragedy for New Zealand, and for New Zealand families, your eloquence last year at the Dalmatian Cultural Centre has stayed with me.
Thank you for all that you said then, and for your messages afterwards.
Today I want to speak in explicit recognition of the fact that in 1979 so much was lost; and the ramifications were immense.
And time hasn't necessarily diminished any of that.
257 people died on the slopes of Mt Erebus on 28 November 1979, 40 years ago today. Let me pause to acknowledge the enormity of that loss, and the effect it has had on the lives of the families – and also on the lives of those who took part in Operation Overdue.
That loss, in and of itself, was huge. It sent ripples across the country, and trauma that those who weren't directly affected would probably struggle to fathom.
But that loss and grief was compounded. It was undeniably worsened by the events that followed. While today is a day for reflection, I feel we will serve you poorly if we don't recognise what has stood in the way, for so many years, of you all having the space to grieve, to mourn and to reflect on the lives of your family members.
Today, of all days, I hope we can say the things that should have been said. I don't need to tell all of you that the accident we are marking today was the subject of two official reports. The first, by the Chief Inspector of Air Accidents, Mr Ron Chippendale, was published on 12 June 1980.
It concluded that the "probable cause" of the disaster was pilot error. I know this finding magnified the grief of many families, particularly devastating the families of the pilots.
The second report, the product of a Royal Commission of Inquiry presided over by a High Court Judge, Justice Mahon, was presented to the Governor-General on 16 April 1981.
Justice Mahon rejected pilot error as the cause of the disaster. Instead, he found that the dominant and effective cause of the accident was the airline's actions in reprogramming the aircraft's navigation system without advising the aircrew.
More controversially, however, the Judge went on to find that witnesses from Air New Zealand had conspired to give false evidence to his inquiry. This led to his report being severely criticised by both Air New Zealand and the then Prime Minister.
When the airline took judicial review proceedings, both the Court of Appeal and the Privy Council found the Judge's findings of conspiracy and deception unsupported and contrary to the principles of natural justice.
But what was lost in all this was the fact that no challenge was made to the Judge's findings as to the cause of the accident.
On the contrary, the Law Lords placed on record their tribute to the brilliant and painstaking investigative work undertaken by the Judge in the course of his inquiry.
They said there was ample supportive evidence at the Judge's inquiry for his conclusions about causation, and noted that his different conclusion from the Chief Inspector was based in part on new evidence before the Judge that was not available to the Chief Inspector.
In particular, the Privy Council said, and I quote, "the Royal Commission Report convincingly clears Captain Collins and First Officer Cassin of any suggestion that negligence on their part had in any way contributed to the disaster.
That is unchallenged." Those findings stood then, and they stand now.
The pilots were not responsible for this tragedy, and I stand here today to state that again.
But these were not findings accepted by the Government of the day.
The Government did not table the report in Parliament. Nearly 20 years went by before the report was finally tabled in 1999. That was wrong.
It caused trauma on top of grief. And persecution on top of pain.
I want to acknowledge, as many in Parliament did when the inquiry was finally tabled, that the way Justice Mahon's report was handled was wrong.
That mishandling was one very difficult feature of the long hard road you have travelled – in the years leading up to the tabling of the report in 1999, and through the years following. In an environment of tumultuous claim and counter claim, of public confusion and ongoing debate, it is difficult I am sure to find a clear place to set down your grief. After 40 long years, you deserve to find that place.
No one can assume to know what that requires though, or even if it's possible. I have read many accounts from family members – letters telling stories of that day, of the weeks that followed, of the trauma that arises any time that Erebus is mentioned.
All I know is that after 40 years, setting down grief will only be made harder, if we don't acknowledge past wrongs. If we accept the Royal Commission's findings on the cause of the accident, which are well established, then the time has come to end the piecemeal acknowledgements.
After 40 years, on behalf of today's Government, the time has come to apologise for the actions of an airline then in full state ownership; which ultimately caused the loss of the aircraft and the loss of those you loved.
This apology is wholehearted and wide-reaching.
We will never know your grief, but I know the time has come to say I am sorry. In making this apology I speak also for and with Air New Zealand.
I know that for many, grievances still exist with the airline. I do not comment on some of the more famous phrases of the Royal Commission of Inquiry except to note what I believe is the change in the Air New Zealand of the 21st century, a company that in form, structure and approach is very different to the Air New Zealand of 1979.
I acknowledge the efforts the airline has itself made over recent years to address your grief, including bringing people from throughout New Zealand, and from overseas, to this gathering today.
Some may say that the past is the past, that we cannot change what happened. That fails to consider that our future is shaped by where we have come from. It is shaped by our response to tragedy and injustice, and by the people who stand up against it.
The past is never just the past.
As we mark the 40th anniversary of an event that remains etched in New Zealand's psyche, we reflect on all that was lost, all that we must learn, and a future that we all must keep striving to make better.
No reira tēnā koutou, tēnā koutou, tēnā koutou katoa.