Crash investigators said New Zealand needs stricter laws to ensure tourists remain safe after finding the pilot of a hot-air balloon probably smoked cannabis last year before taking a fatal flight that killed all 11 on board.
The Transport Accident Investigation Commission today urged politicians to pass stricter rules for pilots, boat captains and other transport operators.
Citing recent fatal crashes, investigators said random drug-testing and zero-tolerance rules were needed.
In their report on the January 2012 balloon accident near the township of Carterton, investigators concluded it was "highly likely" that 53-year-old balloon pilot Lance Hopping smoked marijuana shortly before the flight, which left at 6:40am in good weather.
They concluded he made several errors of judgment: He let the balloon get too low during the flight, he applied the burners when he got near power lines in an attempt to rise above them, and he did not rapidly descend when he was about to strike the lines.
The balloon basket then became entangled in the lines and exploded into flame, the report found.
Two of the passengers jumped out, but died in their falls of about 66ft. The heat then caused the balloon to break free of the wires and rapidly ascend, before crashing into the ground, killing Mr Hopping and the remaining passengers.
Investigators did not directly blame marijuana for the accident, although Chief Commissioner John Marshall said "the possibility that the pilot's judgment was impaired by the use of cannabis cannot be excluded".
Adventure-tourism plays a significant role in New Zealand's economy. About 2.6 million tourists visit each year, according to government statistics, with about one-third participating in sports such as bungee jumping, skydiving or jet-boating.
But safety problems have increasingly come under the spotlight.
"To people thinking of going to New Zealand on an adrenaline sport, think twice," Chris Coker of Britain told the BBC last year.
His son, Bradley Coker, 24, was one of nine people killed in a skydiving plane that crashed in 2010. Investigators found the plane was overloaded.
New Zealand's Ministry of Transport said it is carefully considering the investigators' recommendations.