Good progress is being made on plans for the recovery of the victims of the Pike River mine blast, police say.
Superintendent Gary Knowles said a team of specialists were working on the operation.
"They are working as quickly as possible to develop and confirm options. Throughout all this, the safety of the people involved is our paramount concern. There is no time frame for decisions at this point.
"Our priority is to stabilise the mine environment so that we can then mount a recovery," Mr Knowles said.
The recovery team is looking at a wide range of options to achieve this - including the use of a jet engine, known as a GAG jet. The engine arrived from Australia this morning and is currently being set up in readiness for operation. It is unknown when the machinery will be ready for use.
Mr Knowles said it was just one of a range of options being worked through by the recovery team, with input from mines rescue and a range of specialist advisers.
"Any option we choose will take time to implement and it is likely to be several more days before actual operations to stabilise the mine commence.
"In the meantime we are maintaining close monitoring of gas levels in the mine. It remains a very unstable, volatile environment and all our planning and activity at the mine site has to take this into consideration."
While the recovery team was committed to moving ahead with the operation to return the men from the mine to their families as quickly as possible, the safety of those involved was paramount.