Grey District Mayor Tony Kokshoorn said families of the 29 Pike River mine victims who perished in today's second blast fell to the floor screaming and were in "absolute despair", when they heard the news.
Late this afternoon police confirmed there was an explosion at the West Coast mine and they believe there is no chance any of the miners survived.
Families of the miners were told in Greymouth there was an explosion at 2.37pm, bigger than last Friday's, and all hope was now lost.
Police Superintendent Gary Knowles, who headed the rescue operation, made the announcement to the media.
"Unfortunately I have to inform the public of New Zealand at 2.37pm today there was another massive explosion underground and based on that explosion no one would have survived," Mr Knowles said.
"We are now going into recovery mode. I had to break the news to the family and they were extremely distraught.
"I was at the mine myself when it actually occurred and the blast was prolific, just as severe as the first blast."
Mr Knowles said he was with a rescue team when the blast happened and they were in agreement with him that the miners would have "perished".
Family members were emerging from the meeting crying and some were shouting at media and police. There were a large number of police at the scene.
Victim's father 'still hoping for miracle'
The father of one of the miners who died in the tragedy said he is still holding onto hope.
"I'm still hoping there's a miracle left," Laurie Drew told TVNZ.
Mr Drew was still wearing his 21-year-old son Zen's jacket, which he had donned since the first explosion on Friday.
"I'm so proud of him, as a Dad, but I feel I let him down because I didn't protect him," Mr Drew said.
He said families just wanted the bodies of their loved ones so they can get closure.
West Coast's darkest day
Earlier Grey District mayor Tony Kokshoorn broke down into tears after leaving the briefing and had to go into his council building.
He said this is the "darkest day" for the West Coast.
The families and communities of the dead miners have been changed forever by today's catastrophic blast, he said.
"This has got to be the darkest day for me. For Greymouth, for everywhere. This is the darkest day.
"Things are never going to be the same."
Mr Kokshoorn said the miners' families were angry and distraught at news of the explosion.
Families were left devastated after entering today's police briefing buoyed by the fact camera-mounted robots had entered the mine, he says.
"They were screaming at them. It was absolute despair.
"When the news came everyone just cracked up. People were openly weeping everywhere."
He said families fell to the floor when they heard the news.
"People shouted out in anger, they are sickened by the whole thing. A lot of them felt misled."
Pike River Coal chief executive Peter Whittall said it was still unsafe for a recovery team to enter the mine.
"I still want them back. Their families want them back. We want out boys back. We want them out."
There was no timeline for entering the mine as conditions remained unsafe, he said.
Tragedy not new to West Coast
West Tasman Coast MP Chris Auchinvole was there when the news was delivered and described the family reaction as a "spontaneous outpouring of grief".
"You have to appreciate that when I walked in people were saying 'well Chris, it will be right this time' and in your heart of hearts you wish they [officials] had said that."
Mr Auchinvole said the tragedy would be felt throughout the tight-knit West Coast.
"It's probably a difficult thing to say at this stage but this type of tragedy is not new to the coast. It has been experienced in previous generations and indeed in the current generation."
Pike River mine to be 'gagged'
The Secretary of the EPMU, Andrew Little, told Radio New Zealand that it was believed the Pike River mine would be flooded with carbon dioxide in a process known as "gagging".
The carbon dioxide would clear all oxygen in the mine so that any fires would be extinguished and bodies could be retrieved.
Equipment would be brought over for the process from Australia.
Inquiries to start 'fairly immediately'
Prime Minister John Key will travel to West Coast tomorrow in the hope he can meet with the families and give his condolences.
Energy Minister Gerry Brownlee said the news "was devastating."
He said there would be a range of inquiries into what happened at the mine and they would start "fairly immediately".
Mr Brownlee said he had the same questions in his mind as everybody else about how this could have happened.
"In the long term, of course everyone will want to know what happened up there. It's pretty essential that we find out and the nature of how we achieve that is yet to be determined."
Mr Brownlee said there was no prior warning of concern that had been reported by the Department of Labour.
'The idea that you invest such a huge amount in an undertaking like this, to somehow put it at risk, is somewhat absurd."
Mr Brownlee praised the handling of the incident by Peter Whittall as "impressive".
Coroner to open inquiry tomorrow
The Chief Coroner confirmed he will open a special inquiry into the Pike River mine disaster, starting tomorrow.
Judge Neil McLean says he will begin working on a process that's designed to help the immediate families of the miners.
He says it's too early to say whether an inquest will take place, given the fact that there will be multiple inquiries over time.
Miners wouldn't have suffered
Mine safety expert David Feickert told TVNZ the miners would have not felt the explosion.
"Chances are they became unconscious from the carbon monoxide and wouldn't be affected by the explosion," Mr Fieckert said.
"From the samples today [we know] that there was some kind of heating going on, that provides an ignition force."
He said that given the lack of air ventilation methane gas would have built up a combination between it and the smoldering material would have caused the explosion.