Police command structures slowed the rescue or recovery of the 29 men who died inside the Pike River mine, an Australian gas monitoring expert says.
Darren Brady, of Safety in Mines Testing and Research Station (Simtars) in Queensland, is giving evidence to the Royal Commission of Inquiry into the Pike River disaster.
He was "surprised" to find police in charge of the rescue and recovery operation after being flown to the Pike River mine site, as that would not have happened in Queensland.
Having to put proposals through the hierarchy of police command created delays and sparked "frustration" among those at the mine, he said.
In one example, he was asked to explain a gas reading to someone in charge of decision making who did not understand it.