Labour Minister Kate Wilkinson says all aspects of safety at the Pike River Coal mine will be investigated.
Ms Wilkinson says the Department of Labour employs two inspectors and a mining expert to oversee safety at New Zealand's six underground coal mines.
She says the Pike River Mine was inspected recently.
Ms Wilkinson says the use of check inspections, which are conducted in some Australian mines and can lead to a mine being shut if deemed unsafe, were discounted in New Zealand following advice from the Department of Labour and from abroad.
She says Pike River raises a lot of questions, all of which need answering.