Labour leader David Cunliffe says his party will pay out compensation to the families of the Pike River mine victims if elected in 2014.
He believes the Government has failed in its treatment of the families of the 29 victims.
"This is a failure of leadership by John Key," he says. "It's a failure of moral authority by this government. It is relatively easy to fix this, they just need to do their duty by the families of those miners."
The announcement comes on the third anniversary of the mine explosion on November 19, 2010. However, Mr Cunliffe has denied he is politicising the tragedy.
"I've long believed this an issue that has been addressed squarely and head on."
In July this year, the company that owned the Pike River mine - now in receivership - was ordered to pay $110,000 to each of the families of the dead miners and fined $760,000.
However, the receivers said the company didn't have the money to pay the fine and gave the families just a fraction of the compensation ordered - $5000 each.
If the compensation issue is not sorted by the next election and Labour is voted into power, Mr Cunliffe will front with $3.4 million of taxpayer money for the court-ordered compensation.
He will then put moral pressure on the company's directors and shareholders to pay that money back to the Government.
Today, Mr Cunliffe also issued an ultimatum to stakeholders.
"Pay up now. Get this over with quickly and restore the reputation of your companies because we will not put up with this when we become the Government."
Pressure could come in the form or regulatory, legal, or legislative means or even "a private dinner with the chairs of the relevant companies where they see good sense and decide to take something back to their board".
Mr Cunliffe does not believe the Government payout will set a precedent for future accidents because the circumstances of the Pike River deaths are relatively unique.
He conceded the previous Labour Government could have done more to toughen up regulations.
"This legacy of deregulation and neoliberalism is not limited just to the last four years. But the same ideas that brought us the leaky building syndrome, that brought us the deregulation of our mines, have created an unsafe environment and 29 men paid for it with their lives."
The current National-led Government last week decided it would not step in to pay the remaining amount.
Labour Minister Simon Bridges maintains the Government is honouring the deaths by making sure another Pike River-type incident never happens again.
The Government has taken on board the recommendations of the Royal Commission, which have been implemented.
"We're also honouring what's happened by trying to get back into the mine."
The Government needed to be careful with how taxpayers' money is spent and of the possible precedent paying out compensation could have, he says.