The Government is deferring work on permanently sealing the Pike River mine for a week in the run up to the sixth anniversary of the disaster but says the mine is unsafe to enter.
Environment Minister Dr Nick Smith made the announcement on Sunday, a day after families of the 29 men who died set up a protest camp on the mine road in a bid to get entry to the drift, a tunnel to the mine proper.
"If they want to seal our boys in that mine they'll have to run us down to do it," Anna Osborne, whose husband Milton was one of the Pike River 29, said on Saturday.
The bodies of the men, including two Australians, who died in the November 2010 disaster have never been recovered and state-owned coal miner Solid Energy plans to permanently seal the mine.
The families believe it is safe to enter part of the tunnel into the mine where there may be clues to what happened.
Dr Smith says he has a scheduled meeting with families on Wednesday evening in Greymouth.
Solid Energy has deferred any further work on the site aside from safety inspections for the next week, he says.
"I remain doubtful of claims that the mine can be safely re-entered. The mine is full of methane and is likely to have residual heat sources capable of triggering an explosion if there was a source of oxygen. There is the added risk of rock falls from unstable strata fractured by the 2010 explosions," Dr Smith said.
But the Government recognised it was an emotional time for the families with the first stage of the mine sealing completed last week, and the sixth anniversary of the disaster next weekend.
"We also wish to avoid any tension for Solid Energy staff and its contractors with the protest action blocking the road access to the mine," Dr Smith said.
Solid Energy is working to replace the existing temporary seal with a permanent seal.
This concrete seal 30m down the drift was largely installed last week with about a week's work required to complete it.
The complete mine seal structure also consists of a wall at the portal and the infilling of this last 30m section of the drift and this work is expected to take until early next year.
"I am advised that no new information has come to light in the course of this work that changes Solid Energy's view that safe re-entry of the mine is not possible," Dr Smith said.
He says methane levels in the drift beyond the new seal have been rapidly increasing and are approaching the levels in the remainder of the drift of 95 percent.
The area the failed mine is in is being returned to the Department of Conservation for inclusion in the Paparoa National Park.