Connor Hayes, 25, and girlfriend Joanna Lam, 24, died when a landslide pushed their rented motorhome off Haast Pass into a swollen Haast River on September 10, last year.
Ms Lam's body later washed up on a beach some 55km away, but Mr Hayes' body was never found.
Wreckage from the campervan was recovered from the river during a massive search operation.
Today at a joint inquest before Coroner David Crerar in Greymouth, Haast police officer, Senior constable Robin Manera told of the events leading up to the pair's deaths.
The young couple had arrived in New Zealand two weeks before radiographer Ms Lam was due to start new job at Nelson Hospital on September 15.
They decided to do some travelling before then, and had rented a white VW campervan from a Nelson rental company on September 9.
The next day they enjoyed a guided walk on Fox Glacier before arriving at Haast River Top 10 Holiday Park about 4.45pm.
Manager Norma Dougan told Ms Lam the camp was closed due to the bad weather, and that the next town was Wanaka - a two-hour drive.
Ms Lam asked to use the camp's computer or her phone to contact work and family but Ms Dougan advised the internet connection could not be guaranteed due to the stormy weather. There was strong northwest winds and galeforce wind warnings in place.
They ate at the local Haast pub before leaving about 5.35pm - that was the last time they were seen alive.
It was six days before they were reported missing.
On the second day of a massive search operation, wreckage was found in the Haast River gorge.
The subsequent police investigation established that Haast woman, Dayna Buchanan had been driving that night, headed for Dunedin - a trip she did once a month.
In the worst conditions she'd seen, Ms Buchanan was following a white campervan when she had to stop to free some debris which had got caught up in her car. The campervan carried on.
Two people, including an experienced local road worker William John Caird, stopped to help her remove the sticks.
She went on her way and followed Mr Caird, who'd worked in the area for 33 years, along the pass. He called his bosses about 7.30pm to close the road, he told the inquest today.
About 8pm, at an area called The Trickle, just past Diana Falls, Mr Caird and Ms Buchanan had to stop due to a slip blocking the road.
A white campervan was on the other side of the slip that consisted of a large tree and shingle.
One of the party shone a torch at the campervan and told them to turnaround, but got no response. Ms Buchanan told the hearing that she couldn't tell if it was the same white campervan she'd earlier been following, as its headlights were "blinding", and it was raining heavily.
Ms Buchanan abandoned her car there and got a lift back to Haast.
Later police inquiries established there had been two slips on the road - the second one 800m past the first.
Mr Manera said subsequent enquiries show it was the second slip that wiped out Mr Hayes and Ms Lam.
It wasn't known whether the pair were inside the van at the time of the slip.
Ms Lam's body was found on September 20, on a beach 6km north of the mouth of the Haast River mouth, 55km from the wreckage.
He told the hearing that Mr Hayes' body has not been found. His bank account has not been accessed and there were no suspicious circumstances.
Bernie and Kath Monk, whose son Michael died in the Pike River mining tragedy, represented the Hayes family at the inquest. There were no representatives from the Lam family.
Mrs Monk read out a statement by Connor's father Michael Hayes where he spoke about the overwhelming support and sympathy he's received from the
West Coast community and advised that he hopes to return to Greymouth to take part in the second part of the inquest.
Coroner Crerar issued a finding today on their deaths which he hoped would ``satisfy the legal requirements for both families''.
Given that Mr Hayes' body has never been found, he was "satisfied to quite a high degree'' that both he, and Ms Lam, died near Diana Falls on September 10 last year after their campervan was "struck by avalanche of trees, rocks and associated debris'' which pushed them off the road, down a cliff, into the Haast River, causing them to die from "high energy impact injuries'' to the head, chest, spine, and limbs.
He passed on his sympathy to the families, saying: "It's a tragedy for young ones, prime of life, just starting out on a new job, out here in New Zealand ... it's awful families have lost children in these circumstances''.
Coroner Crerar adjourned the hearing until a later date when the circumstances of the deaths will be investigated more fully.
