A hot air balloon pilot says showing people how to turn off the gas in a balloon is potentially lethal for those on board.
The New Zealand Civil Aviation Authority (CAA) is advising operators to brief passengers before their flight on how to shut off the gas.
The CAA move followed a European Aviation Safety Agency advisory which said that passengers were more likely to survive after a fire starts if there was an easy and quick way to shut off the main gas outlet.
Pilot Denis Hall said instructing passengers on how to turn off the gas was like showing them how to turn off the engine of an aircraft.
"The idea of actually briefing them and giving them a sense of having some control... I think that would be a mistake because people can conceal a tank behind them and could be turning off the taps without you knowing, and that could be really dangerous," Mr Hall said.
He said passengers could sometimes block a pilot's immediate access to the tank while in flight, which was easy to manage with simple instruction.
But it was difficult to imagine a situation where a passenger would make a decision over and above the pilot to turn off the valves.
Mr Hall said passenger knowledge would not have made any difference to the outcome of the Carterton balloon crash in 2012, in which 11 people were tragically killed.
"I know exactly what happened in that accident and I can tell you that turning the tanks off would have made absolutely no difference to what happened."
Propane fuel cylinders used in hot air balloons were usually opened with either a multi-turn or a quarter-turn valve.
The European safety agency was also recommending operators switch to approved quarter-turn valves which were easy to operate.