WorkSafe NZ in 2013 decided to drop charges against Whittall as long as he paid $3.41million to the two survivors and families of men who died but this was appealed by the Court of Appeal..
Family members of the two deceased mine workers who were trapped in the mine, Sonya Rockhouse and Anna Osborne, began court action in 2014 seeking a judicial review of the WorkSafe decision.
WorkSafe CEO Nicole Rosie said the court's decision clarified the approach the regulator should have taken, and would take in the future.
"We hope this decision will bring some relief to the families and we will be seeking a meeting with them shortly to discuss the decision," Rosie said.
"As a result of the families' commitment to their loved ones, New Zealand has new health and safety legislation and a regulatory unit focused on high hazard activities. There is now far greater recognition and commitment to health and safety across the country."