Like every New Zealander, Prime Minister John Key had hoped for the miracle that at least some or all of the 29 Pike River miners had survived last Friday's blast.

"In my heart of hearts I just hoped that there would be some miners or all of them that had somehow found a way to safety."

That hope ended with yesterday's second and significantly larger explosion in the mine.

"It's the finality of the second explosion that rips at the guts of the country," he told media last night.

Mr Key said he was devastated by the tragedy and was sending his condolences to the families of the men who lost their lives.

"The 29 men whose names and faces we have all come to know, will never walk amongst us again. This is a national tragedy.

"To lose this many brothers at once strikes an agonising blow. Today all New Zealanders grieve for these men. We are a nation in mourning."

"After days of waiting, of both preparing for the worst and hoping for the best, they have been delivered the cruellest of news," he said.

"To all those who have lost a loved one, New Zealand stands shoulder to shoulder with you. Though we cannot possibly feel this pain as you do, we have you in our hearts and our thoughts."

Families lost husbands, fathers and siblings, he said.

"This is tragedy for the people of Greymouth. The loss will be felt in every home."

Mr Key said he would travel to Greymouth today where he hoped to meet the families of the 29 men.

"Obviously this will be a difficult and raw time for the families but I'd like to, if I can, express the enormous loss they must be feeling."

Mr Key said he also hoped to pass on the thoughts of the many thousands of New Zealanders who had contacted his office with messages of sympathy.

He said he had met family members of the miners on his two previous trips to Greymouth.

"Looking in their eyes, you can see their pain, that they just wanted their loved ones back."

He understood the anger that some families had shown about the decision not to enter the mine.

But he said the reason was clear, that it was unsafe to enter the mine, and he was entirely confident that the operation had been run properly. "The range of human emotions is natural and anger is clearly one of those."

He expected that a recovery team would not enter the mine until it was safe.

The incident had already claimed 29 lives, and no more lives should be lost, he said.

However, recovery of the miners' bodies would remain "an absolute priority" as an important part of giving closure to their families.

He would also meet and thank those involved in rescue efforts.

"There's been an enormous number of people involved, not just those who were prepared to potentially put their life on the line to go into the mine but right across from those who were drilling ventilation holes and the Red Cross."

Mr Key said he expected a significant service to farewell the miners would be held in Greymouth as well as a larger national memorial service, probably in Christchurch.

A motion in Parliament tomorrow will acknowledge the tragedy, and the House will rise as a mark of respect.

Flags will fly at half-mast on all Government buildings.

The Government would support families and possibly help out financially, but those discussions had yet to take place. He expected the Government would also offer economic support to the region.

He said a Commission of Inquiry would be confirmed after the Cabinet met on Monday to investigate the cause of the explosion, and other factors.

WHAT JOHN KEY SAID
Message to the families

To all those who have lost a loved one, New Zealand stands shoulder to shoulder with you. Though we can not possibly feel this pain as you do, we have you in our hearts and our thoughts.

On financial help

The Government will support families, possibly financially. Economic support could also be given to the region where the Pike River mine was a significant employer.

On recovery

Recovery of the miners' bodies would remain "an absolute priority" as an important part of giving closure to their families.