The cost of recovering the entry tunnel to the Pike River mine has dramatically increased.
Pike River mine Photo: Supplied / Pike River Recovery Agency
Early estimates in 2017 put the price at $23 million.
That has now doubled to $47m, with another $4m set aside as a contingency.
The increase was approved by Cabinet today, along with a completion date of July or August this year.
The government had originally said it would assess what was involved in moving into the mine's main workings, once it had recovered the entry tunnel.
However the Pike River Recovery Minister, Andrew Little, now said this would not be happening, and work would now finish once crews reach the rockfall just before the main workings.
"The big cost was the fact that a lot of work went in last year to understanding the environment in the mine, preparing for it, changing the approach to ventilation of the mine that put a big delay on it, and we had to carry those overheads for a year more than we had expected."
Pike River mother Sonya Rockhouse said the re-entry project, and the evidence it would unearth, was the best chance families had to see someone held to account for killing their men.
"People ask me why so much money is being spent, to me it's quite simple: it's being spent to try to solve the mass homicide of 29 men. We can't be a country that refuses people justice because it costs too much," she said.
Bernie Monk has battled for nearly a decade to get his son Michael back and to see somebody held accountable for his death.
For him, the news that no assessment will be made of whether the main workings of the mine can be entered means his battle is a long way from finished.
"How can they make this call when the whole idea was to go down 800m - it's never been investigated - [to] make a call before we even get there," Monk said.