The first step towards re-entering the Pike River mine could begin within the month.
The Government has accepted a proposal from Solid Energy to fill the mine's ventilation shaft in order to stabilise its atmosphere and allow mine safety personnel through the mine entrance and into the drift leading to the main mine.
The mine has been sealed since a fatal explosion on 19 November 2010 that killed 29 men.
The plan has been approved by the High Hazards Unit, a new agency in charge of mine safety.
Solid Energy has confirmed the company is finalising plans to fill the ventilation shaft, but work could begin in the next four weeks.
A spokesperson says the material needs to be brought to the portal by air and helicopter companies are still tendering for the work.