Labour leader David Cunliffe has said a government led by him would pay compensation to Pike River families.
He said he would seek to recover the money from Pike River's parent companies.
His comments come on the third anniversary of the tragedy in which 29 men were killed.
"We will then seek to immediately recover the money from the parents' shareholders and directors of Pike River Coal Ltd", Mr Cunliffe told reporters this morning.
"We believe the Government has let the families down, that it has a moral obligation as found in the Commission of Inquiry... and we believe there has been a moral failure of Government here."
Mr Cunliffe said he would be very surprised if as Prime Minister he had to resort to legal action to recover the money.
"The company's shareholders and directors have two choices, one is the easy way, the other is the hard way."
Following payment of the money to the Pike River miners' families, many of whom Mr Cunliffe said were in desperate situations, he would use "the power of the office of the Prime Minister" to ensure the money was recovered from Pike River Coal's shareholders and directors.
That could mean "anything from private dinner with the chairs of the relevant companies where they see good sense and decide to take something back to their boards, or a range of other tools at the Prime Minister's disposal".
Those tools included regulatory, legal or legislative measures.
In July after Pike River was sentenced in the Greymouth District Court for health and safety failings that led to the deaths of 29 miners in November 2010, Judge Jane Farish ordered the company to pay a total of $3.41 million in reparation - $110,000 for the family of each victim and survivors Russell Smith and Daniel Rockhouse.
However the company is in receivership.
Last week Prime Minister John Key confirmed Cabinet had considered, but decided against the Government paying the compensation.
Earlier this morning, Labour Minister Simon Bridges said the Government was honouring the victims of the Pike River disaster by ensuring it never happened again.
"In terms of compensation obviously we have an ACC system that is no faults and there is on our advice no cause of action for the families."
Asked whether there was anything that would change the Government's mind, Mr Bridges said: "The legal position from our position is pretty simple."
Asked about the Government's moral position on compensation, Mr Bridges said: "I don't think we'd get into the moral position".
Mr Bridges said he didn't believe Cabinet discussed moral aspects of the matter when it decided against paying the compensation.
"It was a brief matter raised by the Attorney-General."
"I think morally what we can say is we've taken on board everything the Royal Commission has said. Sixteen hard hitting recommendations that now we've, practically speaking, implemented in full.
"We're also of course honouring what's happened by trying to get back into the mine - $7 million of work there. But as you've heard from a number of others in relation to compensation issues we've got a no fault system that is comprehensive. Outside of that we don't think there's a cause of action."
Meanwhile, Mr Cunliffe denied he was politicizing the third anniversary of the Pike River disaster today by announcing his stance on compensation.
"This is a tragic time for the families, we are not seeking to politicize this, we are seeking to give them some hope that when the Government changes next year if this is not sorted out before then it will be sorted out as a matter of priority."