The company is awaiting a decision from Conservation Minister Nick Smith regarding its proposed Fiordland Link Experience, which would include the monorail journey through conservation land from Kiwi Burn, near the Mavora Lakes, through the Snowdon Forest, to Te Anau Downs.
The $150 million proposal would also include a catamaran trip across Lake Wakatipu and an all-terrain vehicle journey to the monorail terminus at Kiwi Burn.
However, Girish Prayag, of the University of Canterbury's department of management, marketing and entrepreneurship, said the proposal could threaten the region's world heritage park status - which ''conferred to an area, place or region means strong conservation and preservation issues are in place''.
Dr Prayag said while he understood the need to make Milford Sound ''more accessible to visitors'', the proposal went against the pristine image of the region that had been protected for so long.
He said the conflict was not uncommon to world heritage sites, where the issue of whether ''economic imperatives will triumph over heritage conservation'' often arose.
''The monorail plan detracts from the clean and green image that New Zealand is selling abroad.
Dr Prayag believed the monorail would ''dramatically change the landscape of the region''.
If the monorail were to be approved, the damage to the area, the reputation of New Zealand in terms of conservation and the overall image of the country ''would not bear thinking about'', he said.
''Tourism will take a severe blow if we get stripped of World Heritage site status.''
''It's not a question of what other sites around the world are doing or have proposed as visitor facilities, but more about what we want this country and its tourism industry to stand for, the values we want our children to appreciate.''
Last week, Riverstone Holdings director Bob Robertson told the Otago Daily Times the monorail would not go inside the national park, but would be located through the world heritage area - which accounts for nearly one-third of the South Island.
The land which the company had earmarked for the monorail route was not ''pristine'', and the company believed the monorail would be ''the most sympathetic way of transporting people through our country, to give them a maximum impact for the lowest carbon footprint''.
''We've got to stop beating the drum of selling `Pure New Zealand', flying in helicopters ... [meaning] the public never get a chance to ... get up close and personal.
''We've got no interest in doing our journey in a quick way - it's not a `quick way' to Milford, it's about providing the experience.''
Mr Robertson felt the proposal had been the subject of ''media misrepresentation'' and said while the company sought a 200m ''corridor'' for the monorail route, ''most of the time we will not even break the canopy''.
The monorail tracks would be suspended above the ground, supported by rails inserted into the ground about 20m apart which could raise or lower the tracks.
''We don't cut the ground, we go in sympathy with it.''
The route would travel around trees of significance, and the monorail itself ''emits no emissions'', Mr Robertson said.
''It's a prime example of how to create impact in the most ecologically sustainable way.''
