Highland Council's planning committee has unanimously objected to a proposed major upgrade of electricity pylons leading from Beauly to Denny.
The proposed pylons are up to 65m high
Councillors rejected Scottish and Southern Energy's application because they said it would have "significant adverse" impact on certain areas.
The controversial matter will now go forward to a full public inquiry.
Power company SSE claims the new power line is needed to meet green energy targets set by the government.
A special meeting of Highland Council's planning committee was held in Inverness on Wednesday to consider the application.
A presentation was made by SSE officials and objectors also had the opportunity to make their views known.
John Rennilson, the council's planning director, said: "Although the committee recognises that a high voltage electricity transmission system is key for the development of renewable energy in the Highlands, they did not feel that the proposal presented to them today was acceptable."
The committee said it also wanted to wait for a government report on the possible link associated with high voltage overhead power lines and cases of childhood leukaemia.
Mr Rennilson said alternatives to the power line - such as laying it underground - must be explored at the earliest opportunity.
Mr Rennilson said: "This is an important issue and we cannot afford to tread water until the public inquiry in the autumn."
The line would run from Beauly near Inverness to Denny near Falkirk
SSE head of sustainable development, Dr Keith Maclean, said under-grounding would cost much more and mean environmental and maintenance problems.
But he said the option of burying some sections had not been ruled out.
Dr Maclean said: "The under-grounding issue is one that always causes a problem at this voltage.
"Most people's view of an underground line is something under the pavement or under the road, but we are talking about a development in itself the size of a motorway.
"That has serious implications on the environment. It also has serious cost implications."
He added: "We make quite clear in our report there are conditions whereby we would look at under-grounding.
"Our belief with the application was we had not got to that stage.
"We have to listen to what has been said from the consultation process and we will talk to the main stakeholders to look at all options to overcome the remaining concerns that they have."
An objector to the proposal said the line poses a threat to legally protected birds.
Brendan Clouston, a member of campaign group Pylon Pressure, said the line would go through woodland.
Mr Clouston said: "The birds are protected under UK law, they are protected under EU law.
"I don't believe they understand what they were doing. I don't believe they understand the impact on the rare birds.
"These birds are protected and if for some reason we don't have a public inquiry that resolves the matter, which is our first choice, this is not over."
Mr Clouston added: "Public officials have a personal liability to implement this EU law."
Maf Smith, chief executive of renewable energy industry representatives Scottish Renewables, expressed disappointment at the decision.
Mr Smith said: "However, the council obviously sees that providing new capacity is important, and we echo their call to the Scottish Executive to bring all parties around the table and find a way to ensure that new capacity can be delivered."
He added: "The Scottish public represent the 'Silent Majority' in this case and public opinion supports the development of our grid infrastructure to enable renewable energy to meet our future energy needs.
"What cannot happen is that all parties wash their hands of this issue. Highland Council obviously wants to find a way forward and we support that."
The proposed pylons are up to 65m high and the line would pass through the Cairngorm National Park.
Councillors in Stirling called for a public inquiry at meetings in February and March and will take a formal view at the council's planning committee on 4 May.
Clackmannanshire full council raised an objection against the proposal in Februrary.
The authority is not a statutory consultee, but councillors wanted to record their opposition because of their concerns the pylons would impact on the nearby Ochil Hills.
Perth and Kinross Council's planning committee also ruled against the proposal on Wednesday.