Families of the Pike River victims are backing the calls of a former rescue worker who believes the bodies still trapped inside can be retrieved.

Hayden Ferguson was one of the few people to enter Pike River after the fatal explosion in 2010 which took the lives of 29 men, and is speaking out after hearing a proposal for an unmanned re-entry.

Ferguson argues that all unmanned entries have failed, while only manned entries have succeeded.

He said the staged re-entry was called off without warning after they successfully completed the first stage and he would've travelled deeper if he knew that entry would be the only shot.

MORE: Police release more than 13 hours of video inside Pike River mine

Family spokesperson Bernie Monk believes Ferguson's statement is a prompt for Mines Rescue to join the call.

"It's time for Mines Rescue to start voicing this," he said. "What they're saying can be done, they've got to let people know what's going on."

Mr Monk said why it was called off is still an unanswered question.

"All of Mines Rescue throughout the world said it should have been done yet someone is not letting us go in there and we just can't understand why."

Earlier this month, police released for the first time more than 13 hours of video taken inside the Pike River mine drift by a robot four months after the deadly explosion.

It was the fourth robot to enter the devastated West Coast coal mine in March 2011, six days after police handed control to receivers.

MORE: PM says Pike River footage doesn't change anything