Minister for Labour Kate Wilkinson has resigned from the portfolio following a damning Royal Commission report into the Pike River mining disaster.
Prime Minister John Key said Wilkinson believed resigning was the honourable thing to do. She will keep her other Ministerial warrants.
The disaster was put down to two decades during which the Department of Labour and Pike River Coal Limited failed to keep up with international best practice for mine safety.
"I think it's fair to say that this isn't an issue that's solely arisen under our watch. It's been there really for 20 years now. Kate Wilkinson happens to be the Minister of Labour at the time this has taken place," Key said.
He had requested the relevant paperwork the Department of Labour had sent Wilkinson while she was the responsible Minister. The advice given to Wilkinson "gave quite a different picture" to what the Royal Commission report noted was actually going on within the Department and the industry.
"I haven't seen any paper work that suggests any of her actions or inactions were in any way to blame," Key said.
"Even the Royal Commission in its findings says that if you look at the [Department's] statement of intent, and you look at the public documents from the Department, you wouldn't have got a picture that there was a problem," Key said.
In the end the company, "completely and utterly failed to protect their workers."
"As a result of that, they were put at undue risk, and an explosion took place that killed them. But I think the Department, if it had been adopting world's best practice, and keeping up with what was happening in other mining environments like this around the world, would have had a different set of procedures," Key said.
"In effect it deluded itself that it was following the right process when in fact it wasn't."
The Royal Commission said inspectors treated Pike River under a 'high trust model'.
"In fact that trust was mis-placed. While they found problems and errors in their quarterly inspections, they didn't raise them fast enough, or didn't actually physically close the mine down. So I think it will change the way we do things," Key said.
"It is inevitably going to lead to a far more prescriptive regime."
There was no news today on whether heads would also roll at the Department of Labour faction now part of the Ministry for Business, Innovation and Employment (MoBIE). Key said any decisions there were up to MoBIE CEO David Smol.