The Royal Commission on the Pike River Coal mine disaster has heard that concerns mine inspectors raised about their workload were not passed on to the manager whose role was to support them.
The commission has heard evidence this week from the two Department of Labour mine inspectors working in New Zealand at the time of the explosions that killed 29 men.
One of them, Kevin Poynter, said the workload was impossible to manage and he had repeatedly raised concerns at the department's regular mine steering group meetings.
Allan Cooper told the commission his role is to offer support and guidance to inspectors.
However, he said, until the inspectors' evidence was given to the commission, he had no idea of their concerns about workload.
He said the evidence has been a real eye opener.
The commission will hear on Friday from an expert on safe workplace systems and investigations into accidents.
Kathleen Callaghan is the director of the Human Factors Group from the Faculty of Medicine at the University of Auckland.
Part of Ms Callaghan's evidence is expected to be suppressed because it relates to issues which will be presented to the commission at a later date.
The commission will also hear from mining consultant David Stewart, from Minserv Ltd, who carried out an audit of Pike River about six months before the explosions.