The Department of Conservation is calling for public submissions on a proposed tunnel linking Queenstown with Milford Sound.
Milford Dart Ltd has applied to DOC for a concession to build the $150 million tunnel beneath the Humboldt Range.
The 10km tunnel is expected to cut by half travel time between Queenstown and Milford Sound, using specially designed buses.
The public has 40 days to make submissions, which DOC will consider at public hearings.
If approval is given, the proposal will be subject to a resource consent application to the Queenstown Lakes and Southland District Councils.