Paul James Laurie, 61, of the Tasman district, died while hunting with a friend, James Short, in the Kea Basin area near Mt Earnslaw on January 18.
In his findings released yesterday, coroner Ian Telford said both men were experienced hunters and trampers.
Although Mr Laurie was "used to challenging himself in his Queenstown environment", he was not considered someone who took unnecessary risks.
About 1.30pm, the pair were negotiating steep and slippery terrain when they separated, with Mr Short choosing a more conservative route.
"After a short time, Mr Short heard some noises and immediately discovered that Mr Laurie had fallen on to the rocks at the base of the waterfall below," Mr Telford said.
Mr Short estimated his friend had fallen about 30m.
He contacted emergency services and Mr Laurie’s body was found by an air rescue team about 6.30pm.
Mr Telford said Mr Laurie would have "almost certainly" died on impact from trauma sustained from a fall from height.
A toxicology analysis detected cannabis in a blood sample, but the level of the drug, and when it had been ingested, could not be determined.
He was not able to decide whether the presence of the drug, which could cause an "impairment of perception and cognition, and loss of motor co-ordination", contributed to the death.
However, "it goes without saying that the use of this substance, and many like it, significantly amplifies the inherent risks associated with outdoor activities".
Mr Telford requested the Mountain Safety Council (MSC) produce an independent report on the accident.
An MSC media statement said Mr Laurie was an experienced hunter and tramper, but that experience could "sometimes subconsciously lead to a degree of complacency".
"Heuristic traps, also commonly known as ‘mental shortcuts’, are often present in outdoor recreation incidents, occasionally leading to serious consequences in the unforgiving backcountry environment," the statement said.
"It appears that he misperceived the risk associated with the terrain and continued to proceed along his chosen route.
"Meanwhile, his friend chose to deviate on to more conservative terrain, minimising the potential of a high-consequence fall. "
— Guy Williams, PIJF court reporter
