The Mines Rescue Service believes it could be months before any work is done to retrieve bodies from the defunct Pike River Coal mine.
Twenty-nine men were killed in a series of explosions at the West Coast mine which began on 19 November last year.
No one has been in the mine since, as it had been deemed too dangerous. In December, Pike River Coal was placed in receivership.
On Monday police, the receivers and the Mines Rescue Service agreed to investigate options for a re-entry operation.
But the legal counsel for the Mines Rescue Service, Garth Gallaway, told Checkpoint on Tuesday no work can begin until the once-explosive atmosphere inside the mine is stabilised and thinks this will take a month.
Only then can a feasibility study start on whether rescue personnel should enter the mine and retrieve the bodies.
"Funding has to be found for that feasibility study which will involve some considerable resources and a fair amount of money as a result," Mr Gallaway said.
"But it's not just a matter of saying the Mines Rescue want to go in there - they have to be asked to go in there. They have to develop a plan that is safe and viable."
Without a request from the mine's owners, the Mines Rescue Service would have no legal power to enter the mine - even if it wanted to.
Prime Minister John Key says the Government has not ruled out contributing to a feasibility study on the viability of a recovery operation at the mine. However, he has doubts about its chances of success.
"If you look internationally typically, these things are dangerous, complex and take a very long period of time. And the international mine inspectors we've spoken to have said in some instances, you can never get in mines."
Payment for the rest of the mission remains unresolved, with the receivers from PricewaterhouseCoopers saying they do not have money available for what is expected to be a multimillion-dollar project.