Public submissions on a South Island tunnel proposal close on Monday, having been extended by more than two weeks because of intense public interest.
The 10km tunnel would connect Queenstown and Milford through Fiordland National Park, meaning tourists could bypass Te Anau.
By Friday, 357 submissions had been made, the Department of Conservation said.
The company behind the proposal, Milford Dart Limited, says the tunnel, which would only be used by buses, would stimulate the economy by freeing up visitors' travelling time.
Southland mayor Frana Cardno says it would destroy parts of the Fiordland National Park and bypass other sightseeing opportunities.
The submission period closes at 5pm on Monday.