Connor Hayes, 25, and Joanna Lam, 24, both from Canada, were last seen alive in the Haast township on the evening of September 10, 2013.
They were on their way to Wanaka when they were swept to their deaths in one of the slips brought down at Diana Falls, on the steep uphill section of the Haast Pass on State Highway 6.
The campervan they were travelling in was likely hit by an avalanche of rocks, trees and other debris, which swept it off the road and into the Haast River below, Coroner David Crerar said in his findings released today.
Miss Lam's body was recovered about 5km north of the Haast River mouth, shortly after she was reported missing on September 17. Mr Hayes' body was never found.
Ms Lam was found to have died from high energy impact injuries to her chest, head, spine and limbs, Coroner Crerar said in his findings. He found that Mr Hayes would have likely died from similar causes.
Coroner Crerar said the site where the pair were knocked from the road had never been identified as presenting this kind of hazard in the past.
"The deaths of Joanna Lam and Connor Hayes were a result of the tragic coming together of a number of events, the absence of any one of which could have resulted in a totally different outcome," he said.
Although Coroner Crerar said he was satisfied that the New Zealand Transport Agency (NZTA) had taken appropriate measures to ensure the safety and security of road users, he made a number of recommendations.
Coroner Crerar recommended that NZTA continued with infrastructure needs for communication on State Highway 6.
He said since the accident, NZTA had installed radio repeater stations along the Diana Falls slip, to ensure it was monitored properly at all times.
He also recommended a signage board be installed and maintained near the Haast Township, or near the Makaroa Township, to keep travellers along SH6 updated on road and travel conditions.
Coroner Crerar also recommended that barriers be installed at the exit and entrance points of SH6 and that NZTA provide more pamphlet and web advice to tourist drivers visiting New Zealand.
- By Nikki Papatsoumas of NZME. News Service
