"The direct cause of Mr Tornmarck's death is unknown. His death occurred in the context of a mishap in an alpine environment," Deputy Chief Coroner Anna Tutton says in coronial findings released today.
Tornmarck arrived in New Zealand on March 1, 2017, for a hunting and tramping holiday. It was his third visit to the country.
On May 12, he sent a text message to a friend, saying he was going on a "solo-mission up Regina now", adding that he "should be back Tuesday or Wednesday".
Although experienced and otherwise well prepared, he was not carrying a personal locator beacon.
Members of the public later spoke of seeing him in the region. Three hunters talked to him that night, and the following morning, at the Cassel Flat Hut, reporting he seemed optimistic and confident of finding tahr.
On May 17, Tornmarck's friend reported him to police as having failed to return.
An intensive search and rescue operation found Tornmarck's campsite "high up the valley near the head of the creek in an extremely hazardous area", under a large, near-vertical rock which went for 200m directly upwards.
But there was no sign of Tornmarck and the search was called off on May 24.
Another last-ditch search was conducted in January last year, using drones, dogs, professional mountain guides, and LandSAR alpine specialists, but again he was not found.
However, a New Zealand Mountain Safety Council (MSC) review, provided to the coroner, noted that bullet casings found by searchers, matching the calibre carried by Tornmarck, were probably his.
They found it unlikely that he would have been shot by another hunter, or that he had accidentally shot himself, or that he had trouble crossing a river.
The report authors concluded it was "most probable" that Tornmarck fell in trying to either shoot or recover a tahr in the steep and difficult terrain.
The Department of Conservation (DoC) said that although hunter safety attracts "a very small proportion of page visits" on its website, it accepted it could improve information about hazards and risks.
It has vowed to review information for users of remote, challenging and difficult conservation land, such as the whole Karangarua catchment, to "ensure that the messages are consistent between the various DoC channels noting the current messages, while not inconsistent, do have different phrasing".
DoC also said it would establish more standardised wording for hazard warnings for activities in remote, difficult areas to provide "a more robust picture of the hazards and the skill level required", and to review the history of fatalities and/or search and rescue events on conservation lands over the last five years to consider where standardised high-level warning might need to be applied.
It will also work with others in the sector - Game Animal Council, NZSAR, NZDA, Police and MSC - to ensure consistency of approach.
The coroner also endorsed recommendations made by MSC, including that all alpine hunters take a cautious approach to route finding and always consider the fall line for any animal they intend to shoot; that alpine hunters should always hunt in pairs; and that alpine and backcountry hunters should always carry two-way communications devices with them.
"Tragically, it appears that Mr Tornmarck, who had limited experience in the New Zealand West Coast alpine environment, died as a result of his failure to follow many of the basic safety rules of hunting or tramping in the New Zealand alpine environment," Coroner Tutton concluded.
"Mr Tornmarck went alone into an alpine environment described by experienced members of the search team as among the most hazardous and challenging in New Zealand. He failed to fill in the intentions book at the hut in which he stayed the night before setting out and did not take a personal locator beacon with him."
She added: "Information relating to the basic safety rules is freely available. It is not known whether Mr Tornmarck was unaware of those rules or was aware of them but elected to disregard them."
The coroner extended her condolences to Tornmarck's family and friends for their loss.