The Royal Commission on the Pike River mine disaster resumed in Greymouth on Monday.
The inquiry is now in its eighth week of hearing evidence about the explosions at the West Coast coal mine that killed 29 men on 19 November last year.
The focus this week is the Pike River Coal company's health and safety systems and safety culture.
The first witness to appear Monday was Adrian Couchman, who was the mine's safety training coordinator. Mr Couchman has already appeared at the inquiry.
He told the Royal Commission that the mine's contractors were not as safety conscious as other staff.
Mr Couchman said that before any staff could go underground, they had to do a two-week induction course, and a two-hour formal training course.
But external contractors had to hold only a unit standard of general competence and a medical certificate, and do a two hour induction session.
He said contractors' safety standards were not as high because they did not have the depth of knowledge in the coal mining industry.