The incident happened at Mount Nicholas Station, a privately owned 40,000ha property west of Walter Peak, on the western side of Lake Wakatipu.
The man was last night identified as Richard Philip Hyde, of Massachusetts.
Queenstown police said it appeared Mr Hyde was injured after a bus reversed into him in a car park. He was transported to Queenstown Hospital, but died from his injuries.
A police serious crash investigation had begun into the matter.
Southern Discoveries launched the station as a tourism experience in 2014, attracting visitors to one of the few traditional farms left in New Zealand where only horses and dogs were used for mustering.
The company last night said the incident occurred about 1.35pm, when Mr Hyde was visiting the station.
"The vehicle was believed to have been making a slow backing manoeuvre at the time of the incident.
"A full accident and emergency procedure was instigated by the company.
"The visitor was treated at the scene and then airlifted by helicopter to the Lakes District Hospital in Queenstown, where he later died.''
Staff were comforting his wife, who was not travelling with him at the time.
Southern Discoveries chief executive Tim Hunter said all staff were "deeply shocked and saddened'' by the incident.
"Our deepest sympathies go to his family and friends.''
The company was supporting staff involved, and all Queenstown operations had been suspended until further notice.
The company was working with police and the serious crash unit investigating the incident.
All other relevant authorities had been informed.
Mount Nicholas Station could not be contacted last night.
