The final position has been filled in the High Hazards Unit, set up by the Government after the Pike River tragedy.
The explosion in November 2010 prompted an investigation into mine safety, which resulted in a new unit being announced last August to manage hazards in the mining and petroleum sectors.
Wayne Vernon, the latest recruit, will be the chief inspector of petroleum and geothermal. He will lead a team of three inspectors.
In December, Gavin Taylor, a temporary chief inspector of mines, and three mine inspectors were appointed.
Mr Taylor is on loan from his role as chief inspector of coal mines in Queensland until April.