The government is urgently checking safety rules and enforcement measures across all industries following the Royal Commission of Inquiry's damning report on the Pike River mine explosions.
Acting Labour Minister Chris Finlayson, appointed on Monday following Kate Wilkinson's resignation, says he started asking questions as soon as he was given the portfolio.
"I've been in the job for 17 hours and I'm onto it," he told reporters on Tuesday.
"I want that information and I want it fast."
The report on the November 2010 tragedy that killed 29 men identified serious failures by government agencies, heavily criticised the mine's owners and revealed numerous warnings of a potentially catastrophic methane explosion were ignored.
It wants a complete overhaul of mine safety laws, rules and regulations which the government is committed to carrying out.
Mr Finlayson is taking it further and an investigation into the entire spectrum of workplace health and safety is a likely next step.
In other developments on Tuesday:
* Ministry of Business, Innovation and Employment chief executive David Smol, who is responsible for the Department of Labour, apologised for failing to monitor the mine and make sure problems were fixed.
"The system was not effective, we accept that. We are working hard to put it right," he said.
* Mr Smol confirmed the ministry was looking at which of its staff may hold "some responsibility" for the tragedy and said any punishment would be an employment matter - unlikely to be made public.
* The mine's former bosses hit back at accusations in the report that production was put ahead of safety. Lawyers for former directors John Dow, Ray Meyer, Stuart Nattrass and former chief executive Peter Whittall said they disagreed with any suggestions the board did not act appropriately over health and safety.
"The company set out to create a safe, world-class coal mine," they said.
* In parliament, opposition MPs tried to pin the blame on the previous National government, saying it deregulated mining in the early 1990s and drastically reduced the number of mining inspectors.