An Australian mining expert warns it could take some time to put out the fire burning in the Pike River Coal mine.
Professor Bruce Hebblewhite of the University of New South Wales says the next step is to make the atmosphere in the mine inert.
He says carbon dioxide or nitrogen can be pumped down the shaft to remove the explosive atmosphere, allowing searchers to enter.
A machine similar to a jet engine will be used to pump gas into the mine, and one is understood to have left Australia on Wednesday night.
Professor Hebblewhite says recovery of the bodies could take some time, depending on the size of the fire and how long it takes to put out.
David Cliff from the Minerals Industry Safety and Health Centre at the University of Queensland says the explosions would have weakened mine structures and left dangerous buildups of carbon dioxide and carbon monoxide.
He says that if the mine is pumped with nitrogen, and the atmosphere made non-flammable, it would then be possible to enter the mine wearing breathing apparatus.