Speakers urged local people to take action to protect their natural heritage, recreation areas and the district's social wellbeing.
Colin Pemberton, until recently a Department of Conservation (Doc) concession manager, said the proposed Milford Dart commercial bus tunnel linking the Routeburn and Hollyford valleys threatened Hollyford Camp.
Now the last 1930s Public Works camp in existence, it was part of New Zealand's heritage.
The trust that operated the camp and its museum remained totally opposed to the tunnel proposal, he said.
Run-off from the tunnel construction site was also likely to foul the pristine Hollyford River.
"This is another sale of New Zealand's assets - and a crown jewel at that," Mr Pemberton said.
Scientist and conservation activist Sir Alan Mark compared the campaign ahead to the Save Manapouri campaign he spearheaded 40 years ago.
Save Manapouri took local concerns to the nation and eventually swayed the government of the day.
"Government did the courageous thing. The public spoke and the public prevailed. That's got to be the situation here," Sir Alan said last night.
Southland Conservation Board chairwoman Viv Shaw said that in its independent advisory capacity the board had told Doc the proposals were contrary to the Fiordland National Park's management plan.
Doc had approved the proposals nonetheless, so the board had then made submissions against them.
The conservation board would welcome a judicial review if either project got the go-ahead because any approvals could bring a flood of other concession applications that would also contravene the management plan, Dr Shaw said.
Te Anau resident Bill Jarvie said the monorail would mean the building of a construction road through hunting, tramping and fishing areas on Te Anau's doorstep.
The road's "silt load" would pollute pure trout-spawning rivers, and the thousands of concrete beams and pillars, as well as up to four trains travelling at 90kmh, would alter a precious area forever.
There was no way to mitigate the destruction of forest, which would be harmed as far as 50m away from the construction site.
"Can you imagine how destructive this will be to our back-country experience?" he asked.
Hotelier Geoff Thomson warned Te Anau could become like the "ghost towns" along Route 66 in the United States if tourist traffic was diverted away to the new routes.
"Proponents say they will depend on the existing visitor flow. That's a nice way of saying they're going to take our visitors," Mr Thomson said.
The meeting was continuing last night as the ODT went to press.
