The spokesman for the families of the Pike River 29 says some of the information to come out of the third phase of the Royal Commission of Inquiry will be the most damning yet.

It begins in Greymouth this morning.

This phase will examine what happened at the mine, including oversight by the department's mine inspectors, the cause of the explosions and Pike's health and safety systems.

Bernie Monk says the families have been briefed on some of the witness statements.


"It's going to be quite damning to hear a lot of the information that comes out, and I'm sad to say this but there's been a lot of things been set aside here that should never have happened, and it's even worse than the public have realised up until now,'' he says.

The mayor of Grey District is confident charges laid by the Department of Labour in relation to Pike River won't compromise the Royal Commission of Inquiry's third phase.

The Department has laid a total of 25 charges against former Pike River chief executive Peter Whittall, the company itself, and drilling company Valley Longwall International.

Tony Kokshoorn doubts that will lead to witnesses refusing to answer questions.

"I think everybody wants to be transparent and open here. I think they want a good outcome and that is that they want to know why this mine blew up, and we need to prevent these types of explosions happening into the future,'' he says.