Tears, laughs, jeers at the Greymouth Pike River premiere

There were tears, laughter and a standing ovation at the emotional launch of the Pike River film in Greymouth, almost 15 years after the mining disaster in which 29 men lost their lives.

The film tells the story of the tragedy through the eyes of Anna Osborne and Sonya Rockhouse, played by Melanie Lynskey and Robyn Malcolm.

Osborne lost her husband Milton in the disaster and Rockhouse's son Ben also died, while another one of her son's Daniel survived the first explosion and was able to escape.

The two women formed a friendship in the wake of the disaster, joining other family members to seek accountability for the deaths of 29 men they say should never have happened.

Osborne and Rockhouse sat beside Malcolm and Lynskey in the middle of Greymouth's Regent Theatre on a rainy Monday evening, surrounded by other Pike River families and West Coasters for the film's New Zealand premiere.

Lynskey admitted she was feeling nervous, having not yet seen the film. She had a link to view it online, but said it hadn't felt right to watch it from her Los Angeles home.

"I made a decision that I would watch it in Greymouth and now that I'm here I'm like, 'what was I doing? What was I thinking?' It feels very vulnerable, but my own feelings aside, there's a lot of emotion in the room and people have been very kind.

"I'm going to be crying. I have my tissues"

She said her main goal in playing Osborne, was to do her proud.

"She said that to me that the most important thing, was that the love that [she and Milton] had was conveyed and we had such a short time in the film before his character is not there anymore, so that was something I really wanted to get across, that her fight was for Milt, the love of her life."

Malcolm said there was a long list of reasons she wanted to be involved in the project, one being that it told a story of profound injustice that hadn't been put right - and of two women who wouldn't give up.

"I'm just so proud of those two, they've still got so much fight in them and they're still on that bridge and they're not getting off it. So more than anything, they're being vindicated over and over and over again and the story that we're telling about them is part of that."

The emotion in the theatre was palpable at times during the film, with loud jeering during the scene where health and safety charges against former Pike River Coal boss Peter Whittall were dropped.

The Supreme Court later ruled it was unlawful for WorkSafe to withdraw its prosecution of Whittall, in exchange for $3.4 milllion in payments to the victims' families.

Cheers and applause rang out during the scene where Allied Concrete pulled out of the contract to permanently seal the mine.

Osborne and Rockhouse didn't know each other before the mining disaster, and their raw and honest friendship, now being played out on the big screen, drew plenty of laughs from the audience.

Rockhouse said it was their connection that had made the ongoing fight for accountability possible.

"We wouldn't have been able to do it on our own and I think we bonded because we each knew what the other was feeling. People got sick of it after a while and just got sick of hearing about it.

"We never did. We were obsessed and we were angry and there was no one else really we could talk to and so we talked to each other."

Osborne said it was their love for the 29 men that kept them going.

"It's something we should never have had to do in the first place, no one should have been killed in the workplace but 29 guys were killed. We just couldn't let our men stay there without at least trying to bring about justice for them."

Director Rob Sarkies said after meeting Osborne and Rockhouse, he knew it was a story that had to be told.

"The community here, specifically the Pike River families we've been working with want this story told and they really want New Zealanders to understand the human truths of the story, what it's taken to fight and why they have fought it because this should never have happened.

"Fifteen years on, the families are still waiting to see whether there's going to be a police prosecution or not. We're all holding our breath for an announcement, we hope, in the next month or so. I didn't plan this timing, but in a way, it couldn't be better."

Grey District Mayor Tania Gibson said the event was marked with anticipation and emotion and she thanked those behind the film for the care and the respect they had shown in telling it.

"We all remember where we were that day, the shock, the sadness, the devastation that ripped through our district and the country. The loss was felt by every person on the Coast and it remains part of who we are.

"May [the film] honour those we lost, recognise those who still carry the pain, and remind us of the strength of our people and our community, and let us not forget the men that we lost."

Pike River premieres in Auckland on Tuesday night and is in cinemas from 30 October.