Via Ferrata mountaineering instructor Chris Prudden said the soldiers were climbing in Queenstown as part of their adventure training with the company.
They also mountain biked and canyoned around the district.
They were in Queenstown for five days at the end of their five-week stay in New Zealand, during which they trained at Tekapo and Burnham.
Mr Prudden, who has been involved in mountains and climbing as an amateur and professional for more than 30 years, said the experience was "quite intense".
"Apart from them getting through it and doing the activities, it was quite intense for us.
We wanted to get them through without any incident.
"For us, it was a busy five days."
Mr Prudden said the Via Ferrata - "a couple of minutes out of Queenstown" - was officially opened by then prime minister Helen Clark about five or six years ago.
