The aim of both is to shave hours off the trip between Queenstown and Milford Sound, which currently takes a laborious five hours by road.
Opponents say this is irrelevant. Their ideal tourists are those with the time and money to leisurely absorb the area's raw grandeur. They see no need to speed up journeys through the scenery, and want nothing to do with those who come to see as much as possible in as short a time as possible.
That line of thinking puts a severe cap on the area's tourism potential, of course. As the promoter of the Fiordland Link Experience has pointed out, it also runs contrary to the call by the Tourism Industry Association's Martin Snedden for the industry to adapt its offerings to what visitors want.
A balance can be struck here. Indeed, if the right development is chosen, New Zealand can establish a reputation for excellence in environmental tourism.
Nobody wants vast tracts of Fiordland ravaged in the interests of tourism. That would be self-defeating. But Norway, a country offering a similar experience, illustrates what is possible. Its most popular fjord trip provides easy access for tourists through a return trip from Bergen that includes train, boat and bus travel.
The monorail, catamaran and all-terrain vehicle proposal has a similar feel. But it has also attracted considerable opposition because the monorail would require the clearance and modification of 68ha of forest. This, according to Forest and Bird, is home to endangered bat species and threatened forest birds.
The promoters have done their best to offset this by powering the monorail with renewable energy and staying outside the boundaries of the Fiordland National Park. They also seem confident of being able to achieve a profit.
It may be, however, that the bus tunnel, which would pass under national park land and Fiordland's Humboldt Mountains, offers the more direct and less intrusive way to slash time off the trip to Milford Sound. It has suffered less criticism from conservationists, although they will not exactly be queuing to applaud it when the proposals are considered by the Department of Conservation.
The two developers say they do not see their proposals as being in direct competition. But the need to safeguard the environment as far as possible while improving access means, in reality, that only one should be approved. Too much development would, indeed, lead high-end tourists intent on experiencing the wilderness to recoil from visiting this country. Conversely, however, restricting the journey between two of NZ's most popular visitor attractions to a relatively limited number of travellers is hardly the recipe for a vibrant, healthy and growing tourism industry.
