The re-entry of the Pike River Coal Mine is still some way off.
The Government announced $7.2 million funding for Solid Energy's plan to re-enter the mine last August. The work was expected to take about six months.
Solid Energy spokesman Bryn Somerville said delays were partly due to bad weather.
"We have always said we are going to do it right and do it safe. It's been more complicated than we thought," he said.
The re-entry effort had completed the project's first three stages which involved plugging the main ventilation shaft, drilling new boreholes and checking the area with a camera.
The next four stages - plugging the tunnel with cement foam, pumping in inert nitrogen, ventilating the tunnel and re-entering - could happen quickly but would not start until every detail was covered.
- Fairfax Media