Despite considerable evidence of a troubled safety culture at the mine, which emerged from the year-long Royal Commission into the disaster, prosecutors claimed there was a lack of evidence against Whittall.

"Taking into account the available evidence, the ministry considered that the likelihood of obtaining a conviction was low," New Zealand Ministry of Business, Innovation and Employment health and safety acting deputy chief executive Geoffrey Podger said on Thursday, according to AAP.

He placed blame on “a number of witnesses” who did not want to go to court and said some experts clashed in their evidence.

Yet the court of public opinion is another matter, with opposition parliamentarians, union officials and families of the victims scything the government back down.

The Engineering, Printing and Manufacturing Union – which also represents miners – called the decision disgraceful and said it defied belief that Whittall got to walk away.

“Twenty-nine men died at Pike River because of a culture which persecuted the union and put profits ahead of safety,” EPMU assistant national secretary Ged O’Connell said.

“Peter Whittall should still be in court.

“The government should show it will hold business accountable when people are killed at work by introducing corporate manslaughter legislation and scrapping their anti-union laws.”

NZ Labour Party Member for West-Coast Tasman Damien O’Connor hinted that there were political reasons behind the decision to drop the charges by the former Department of Labour against Whittall – with the Royal Commission revealing widespread inadequacies on the mine inspection front.

“The government department knows full well any trial will further scrutinise the list of failings that contributed to this disaster,” O’Connor said.

While Whittall’s legal team told the hearing that he would pay the previously court-ordered $NZ3.4 million ($A3.1 million) compensation package to the dead miners’ families on behalf of the former PRC board, which equates to $110,000 each, O’Connor said it was never about the money.

“The families have said they want justice more than money and this tragedy will have no end until justice is seen to be done,” he said.

“This looks like a closed-door deal, which again denies the grieving families justice and it is understandable they are furious with what looks like a stitch-up.”

Various family members labelled the compensation as “blood money” to the media.

According to AFP, Bernie Monk, who lost a son in the disaster, said justice wasn’t served.

"We've always said this disaster made a laughing stock of mining – the justice system now is in the same place," he reportedly said.

Neville Rockhouse, who lost one son while his other son was one of the two miners who miraculously survived the first Pike River explosion, told TVNZ he was gutted that charges were dropped against Whittall.

“This is so unjust it is just incredible and corporates can pretty much do what they please – that’s the message that comes out of this whole sorry terrible tragedy,” he told television reporters outside the Christchurch District Court.

While Whittall offered to meet the families, Rockhouse and others have refused.

Some of the victims’ families are in need of the compensation money while others have indicated they will not accept it.

PRC is in receivership, with state-owned Solid Energy buying the mine assets in 2012.

Solid started another mine re-entry program in November with the aim to explore the access tunnel down to where it was blocked by a rockfall about 2.3km in from the mine portal.

Explosive risks from the sealed gassy mine workings threaten any effort to possibly recover bodies of the 29 men killed by the 2010 disaster.