Approval for a major upgrade of pylons through the Cairngorms would blight the face of the national park, according to a new campaign group.
Campaigners produced an image of how they say the area will look
Cairngorms Revolt Against Pylons has urged the Scottish Executive not to "rubber stamp" the 67m-tall pylons.
The route, which cuts through the area where the BBC's Monarch of the Glen is filmed, is part of a planned 180-mile upgrade between Beauly and Denny.
An executive spokesman said it had not yet received a formal application.
The campaign group said the electricity transmission pylons were each the size of the Statue of Liberty.
It has also called on energy firm Scottish and Southern Energy to bury the line underground where it passes through Cairngorm National Park.
Spokesman Roy Tylden-Wright said: "If the Scottish Executive rubber stamp these plans it will be failing in its duty to protect Scotland's second national park.
"Imagine how America's image abroad would suffer if the government agreed to the construction of monster pylons through Yellowstone National Park?"
Mr Tylden-Wright said that at twice the height of existing pylons in the Highlands the planned route would dominate the park entrances at Kinlochlaggan, Drumochter Pass and the Corrieyairack Pass.
He said this was one of Europe's last wild landscapes and warned the project could have a disastrous impact on tourism.
"The southwest entrance will look more like an industrial park than a national park," he added.
The group said that more than a quarter of tourists surveyed by VisitScotland in 2003 said they would avoid parts of the countryside with electricity pylons, mobile phone masts and wind farms.
Cairngorms Revolt Against Pylons said the additional cost of laying the cables underground had to be measured against potential decades of lost revenue from reduced tourism.
The cast of Monarch of the Glen on location
The group estimated that laying the cables underground would cost between 10 and 15 times more than building overhead lines.
The area around Loch Laggan has become famed worldwide as the backdrop for the popular Monarch of the Glen series.
The electricity firm said it had tried to keep visual intrusion to a minimum.
Scottish and Southern Energy said the pylon line was essential to ship power produced by new wind farms and hydro schemes in the Highlands and islands to customers further south.
The firm's Keith MacLean said: "Renewable energy is best harvested well away from where the population is, so we need the wires to bridge the gap.
"We've worked hard to try to minimise the impact of the new line and indeed there will be just over half the number of pylons there were before."
A spokesman for the executive said: "To construct this overhead line, Scottish and Southern Energy would require consent from the Scottish ministers.
"Although we are aware of the proposed overhead line, a formal application has not yet been received."