A group of 21 archaeologists have said the plan for a tunnel near Stonehenge will have "dreadful consequences" for the World Heritage site.
In a submission to the government, the academics claim the tunnel approach will be a "visual blemish" and ruin views of the winter solstice sunset.
They also warn it will place the area's future archaeology at risk and cause a "destructive impact" to the site.
Highways England says a tunnel will cut congestion and improve journey times.
The busy A303 currently passes within a few hundred metres of the ancient Wiltshire monument.
The 1.8 mile (2.9 km) dual carriageway tunnel proposal forms part of a £2bn government scheme to upgrade all remaining sections of the road between the M3 and M5.
Less damaging option
The tunnel plan has the backing of English Heritage and the National Trust.
A report by UNESCO and the International Council on Monuments and Sites has also recognised the benefits of the project.
However, the group of archaeologists, which includes Mike Parker Pearson, professor of archaeology at the University of Sheffield and the University of Buckingham's Prof David Jacques warn that the proposed tunnel entrance and approach road will be "a vast gash on the landscape".
They believe a southern bypass is the only option which will not severely impact the site. They also argue it would be cheaper to build and less damaging to the landscape.
The academics say advances in technology mean the area could still offer up further major archaeological revelations "if the monuments and their precious setting are not wrecked".
"Planning at Stonehenge must be cautious and always propose minimal intervention," they added.
A spokesman for Highways England said: "We are working closely with key organisations within the World Heritage site, and we continue to find the best solution possible to improve journeys for drivers while also protecting Stonehenge."
He said a public consultation on the tunnel plan, which runs until 5 March, is "offering people the chance to see our initial proposals and we have been exploring fully the potential locations for the tunnel".
"For now, we can only identify broad possible locations for the tunnel portals but the plan is to put them beyond the horizons of the stones," he added.