Milford Dart Limited has also suggested an 11.3km tunnel behind Glenorchy.
Both plans run through Department of Conservation land and the department is expected to make a decision on whether it proceeds with the proposals by the end of the year.
Ms Cardno, from Te Anau, said Fiordland belonged not only to New Zealand but the whole world.
Other world heritage areas had lost that status and suffered a drop in tourism as a result on development, she said.
"The greedy ones who say 'we want to do this' actually can harm the tourism market, because it's ruining our world heritage areas."
Ms Cardno said the monorail would not bring any more tourism revenue to the region but would alter the tourist flow, affecting 29 small communities.
Ms Cardno said she loved the Hollyford Valley where the tunnel would be started.
"It's a real spiritual experience and to be there where there's nothing man-made, it's amazing."
The petition, which has gathered some 25,000 signatures online so far, will be handed to Parliament for consideration by the Local Government and Environment Select Committee.