Police are yet to decide whether their own staff will enter the Pike River mine, raising concerns by a forensics expert that any mishandling of evidence could jeopardise a future court case.
The mine is a crime scene and Pike family spokesperson Bernie Monk says police will have to go in as part of the planned re-entry.
"The police have got to be part of this because it's still a crime scene. Forensically, they will have to go in," he said.
But it's a decision police are yet to make.
Dave Gawn of the Pike River Recovery Agency said he thinks the police stance is entirely appropriate.
"They need to have absolute assurance that their police, if they do go underground, are safe."
Machinery, equipment and human remains could be found inside.
But a top forensic scientist, Sean Doyle, says evidence could be at risk if experts aren't handling it.
"It can be fatal. The integrity of any sample that's recovered is very important. And if the integrity in terms of any contamination or tampering is possible, and the item has not been managed according to good practice, then it may well be that the evidence that might be adduced from the item is ruled inadmissible," he said.
Police have told 1 NEWS that the safety of their staff is paramount and they will now conduct their own risk assessment of the re-entry plan to see if their staff will enter the mine or not.
If they don't, mine experts will be trained by police in forensic techniques.
"I'm confident in the police, their ability to train us if that is required, but also the procedures and processes that they will have in place as we bring out exhibits or evidence or, for that matter, human remains should there be any in the mine," Mr Gawn said.
Police have been involved in the plans from the start, and could use cameras in the mine to help monitor evidence gathering.
Pike River Re-entry Minister Andrew Little said if police don't go in, their advice will be needed.
"If there are human remains, if there is anything that looks suspicious, then if the police don't go in we will need their advice. And they will want to be there, available to give that advice," Mr Little said.
Police will meet with the families and mine experts in Greymouth next week to talk more about their re-entry role.