More than 100 people died in New Zealand workplaces every year and more than 400 workers were seriously injured. Many others were less seriously hurt.
"You could literally fill Eden Park four times every year with those injured in our workplaces."
Mr Jager made his comments at a press conference, sitting beside David Smol, the chief executive of the Ministry of Business, Innovation and Employment which is now the Government's regulator of health and safety in the workplace.
The royal commission report was highly critical of the Government regulator which allowed the mines inspectorate to run down to two staff in 2010.
Mr Smol issued a formal apology: "I apologise for the failure to be more effective as a regulator and the insufficient focus on health and safety in the Department of Labour."
He said many former Labour Department staff with direct line accountability for health and safety in the lead-up to the Pike River mine explosion had left and he would take legal advice on further action.
Labour MP Darien Fenton used the snap debate on the issue to accuse the former minister of narrowing an inquiry into mining initiated by Labour to just focus on small mines, of rejecting a call for union "check inspectors" and for dismissing a letter from Labour MP Damian O'Connor in May 2010 expressing concerns about mine inspections.
"She [former Minister of Labour Kate Wilkinson] stood on the stage with the Prime Minister at the memorial for the Pike River Mine deaths. She wanted to be part of that, but she wanted no part in making the real change that was needed."
National's Gerry Brownlee interjected that former Conservation Minister Chris Carter stopped a second portal from the mine.
"You write history to suit yourselves," he told Labour.
Green MP Kevin Hague said a "wave of ideology" towards small government in the 1980s and 1990s led to the disaster.
Regulations were stripped away, and there was a catastrophic failure of government as a regulator.
The two mines inspectors had repeatedly called for greater resources to do their jobs, were not trained in systems audits and were unclear on how to interpret the standard.
"It is the failure of the regulatory regime, of the Government as a regulator, and it is the failure of deregulation that has led to a situation where this company, Pike River Coal, could take those catastrophic risks."
New Zealand First MP Denis O'Rourke said Prime Minister John Key was wrong in saying the primary responsibility lay with the company.
"It is a matter for the Government to ensure a robust safety culture."
