Pike River re-entry 'by the end of this year' - Andrew Little

While there is no official date set yet, Pike River Minister Andrew Little says re-entry into the mine by the end of the year is likely.

The minister told The AM Show on Monday it's now just a question of working out the details.

"All the advice and plans say this is doable and achievable, it's now just a question about working out the detail of what you have to do - ventilating the mine, purging it of the gas, the staged re-entry process - but it is all technically doable.

"I'm pretty confident we will start the job by the end of this year."

Mr Little says the question of the final cost remains, but that won't be a major deterrent. 

"We're pretty sure now it will exceed the $23 million budget we set up at the end of last year.

"It's not just a question of doing it for its own sake; it's about the families and the real possibility that there will be human remains we can recover at the far end of the drift.

"There's also the other question of getting a more accurate sense of what actually happened, a more accurate explanation about what was the cause, what could've happened and therefore who might be responsible."

As the re-entry to the Pike River Mine gets closer, so does the new police investigation.

Pike River families' spokesperson Bernie Monk told The AM Show it's been an ongoing battle.

"We go back to 2013-14 when the authorities walked away from any investigative work.

"We look at the [Royal Commission into the Pike River Mine Tragedy] that only investigated up to the first explosion. All the questions our lawyers made in that commission to bring justice and accountability for the families, and their lawyers got up and said 'don't answer those questions, you could incriminate yourself'. That left a very bad taste in our mouths."

Mr Monk says despite the regular dangers of their work and even with the further safety breaches, the victims could have never seen the explosion coming.

"A lot of those men went to the authority and complained and complained and complained.

"I look at my son, he was a contractor. He wouldn't have known about the dangers of entering that mine every day, and that's one of the things that really frustrates me. The authorities just told them to get on with the job."

Mr Little says he's as keen as the families to have a clear assessment about who is responsible.

"We always intended right from the outset that the police would be involved, we would treat the drift as a crime scene. There needs to be a forensic approach taken as we make re-entry."

The minister said the major problem is the "dodgy deal" done with Pike River mine boss Peter Whittall.

"It was an arrangement that the Supreme Court has declared to be unlawful, whereby he has walked away and charges against him dropped. The double jeopardy rule will mean it's pretty hard to chase him… It's a disgrace for our justice system that we allowed it to happen.

"There's a question then about whether the directors of the company might be held liable or others might be, that's why [re-entry] is important."

Mr Little says it is likely some human remains will be found on re-entry.

"There are photos of what looks like bodies from the cameras that have been put down there.

"The fact that two guys managed to get out of the mine, the chance that others got part way up the drift as well is very high and we want that to be covered off.

"If there are human remains we need to have a proper disaster victim identification approach to recovering those remains."

For the Pike River families at least, it couldn't come soon enough.