Proposed mega-developments to enhance the journey between two of New Zealand's most popular visitor attractions have opponents warning that life in a precious World Heritage Area and national parks will suffer.
But those behind the two planned developments for travel between Queenstown and Fiordland - including a monorail which could prove to be the longest in the world - say they will provide a much-needed lift for New Zealand tourism.
The first proposal is the $150 million Fiordland Link Experience which would include a 41km monorail trip through conservation land that takes in Te Wahipounamu (South West New Zealand) World Heritage Area. The monorail would link tourists with catamaran and all-terrain vehicle trips.
The second is an 11km bus tunnel called the Milford Dart, costing up to $170 million Those behind it say it would cut travel time for a one-way trip from five hours to two for some of the half-million tourists who visit Milford Sound every year.
Forest and Bird warns both developments would have significant impacts, especially the monorail proposal which it says would require clearance and modification of 68ha of forest, home to endangered bat species and threatened forest birds.
"Neither of the proposals is essential. The public and tourists already have access by way of public roads to these areas in the national parks and the jury is out as to whether they would alleviate congestion at Milford."
Riverstone Holdings - the company behind the monorail proposal - has hit back, with chief executive Bob Robertson saying: "Forest and Bird can flap their wings all they like but I think people in New Zealand would like to earn a reasonable living. Tourism is very important.
"Once the monorail is there it will be the same environmental impact whether it's one person using it or one million."
Conservation Minister Kate Wilkinson has given notice of her intention to grant concessions for the parties to investigate, construct, operate and maintain the two projects on the public conservation land, and public submissions are being taken ahead of hearings on both.
Southland district mayor Frana Cardno said that aside from her "extreme concern" about environmental effects from the Milford Dart tunnel, there was no need to speed up journeys through the scenery.
"We need to have quality tourism in New Zealand, and there's already perfectly adequate ways of getting to Milford. What we have got to do is slow people and let them enjoy that magnificent drive."
Milford Dart Ltd managing director Tom Elworthy said he suspected some of the opposition to the project was motivated by reasons other than environmental.
"I guess there's people that just have an issue with the fact of a tunnel being in a national park. I suppose if we started outside the national park and ended outside the national park, I imagine people possibly would still have a problem because of the fact it's there - even though you can't see or hear it."
Mr Elworthy said he did not see the Fiordland Link Experience as direct competition to the Milford Dart. Mr Robertson said it might be that there was room for only one of the two developments, and he backed his monorail as more likely to succeed.
Getting from A to B
The Fiordland Link Experience, over 106km, would start with a 20km catamaran trip on Queenstown's Lake Wakatipu, before linking with an all-terrain vehicle for 45km, onto a 41km monorail trip through Snowdon Forest to a terminus at Te Anau Downs, in Fiordland National Park.
The 11.3km Milford Dart tunnel would link the Routeburn Road in Mt Aspiring National Park to the Hollyford Road in Fiordland National Park, passing under national park land and Fiordland's Humboldt Mountains.
The Department of Conservation is taking submissions on both proposals.