A drug education campaign is being launched by the aviation industry regulator following positive cannabis tests found by investigators in two crashes which killed 20 people.
An interim report released by the Transport Accident Investigation Commission (TAIC) on Thursday showed Lance Hopping, the pilot of the balloon which crashed in the Wairarapa town of Carterton on January 7, killing 11 people, had cannabis in his system.
It comes a day after it was revealed two tandem jumpmasters in a skydiving plane which crashed in Fox Glacier in September 2010, killing nine, also tested positive for cannabis.
"I am very disappointed by evidence of drug use noted in recent TAIC reports," Civil Aviation Authority (CAA) director Graeme Harris said.
"The CAA is planning an education and safety promotion campaign on this issue, consistent with the advice provided to the commission by the Ministry of Transport in its report into the Fox Glacier accident released yesterday."
Investigators said the cannabis use didn't contribute to the Fox Glacier crash, while it was too early to tell if it was a factor in the Carterton crash.
TAIC investigator Ian McClelland says cannabis use is a concern, but when asked if it's rife in the sector he said "we've only had two accidents where it's been identified in the last two years".
He says there's no legislative requirement at present for random or compulsory testing.
Prime Minister John Key, who is also Tourism Minister, says adventure tour operators should never smoke drugs or drink before taking paying customers on risky rides.
"In my view it is totally unacceptable to have people offering adventure tourism and having significant drug and alcohol in their system."
In the Fox Glacier report, the commission recommended a drug and alcohol testing regime be introduced in the aviation adventure industry.
It also cited lack of regulation of the aviation adventure industry as a problem, prompting the father of an English victim to say adventure tourists should think twice about visiting New Zealand.
Mr Harris said regulation of the ballooning industry had improved dramatically since January's crash.
The final TAIC report into the balloon crash is likely to be a year away.