The miners' union has labelled former Pike River Coal directors' criticism of royal commission of inquiry findings "disgraceful", and says they are trying to blame underlings for the disaster.
John Dow, Ray Meyer and Stuart Nattrass were directors of Pike River Coal at the time of the explosion at the West Coast underground mine, where 29 men were killed in November, 2010.
On Wednesday, they hit back at the findings of the royal commission of inquiry into the disaster, saying they never put profit before safety.
The Engineering, Printing and Manufacturing Union (EPMU), in a responding statement, accused them of trying to shift responsibility.
It was disgraceful and showed the need for stronger mine safety laws and a corporate manslaughter charge, said the EPMU's Ged O'Connell.
They were trying to blame the former health and safety officer Neville Rockhouse, whose sone Ben was killed in the mine, for their failings, he said.
"There is no doubt Pike River Coal put production ahead of safety, and the royal commission report gives numerous concrete examples of this happening."
Mr O'Connell said the inquiry heard repeatedly how the company refused to listen to workers, excluded the union at every opportunity.
But the three directors said the union was aware of how the mine was run, along with safety officials and other experts.
"None of these individuals or organisations expressed concerns to the company's management in relation to safety at the time," the directors said.
They accused the commission of basing its view upon conjecture or impression, and not the evidence.
"The company's board never rejected a health and safety request on financial grounds or because it might have impacted upon production," the directors said.
Former Pike River chief executive Peter Whittall is fighting health and safety charges laid against him, while police are still investigating any possible criminal charges.