Scotland's mountains are still not being properly protected from damaging vehicle tracks, according to a coalition of environmental groups.
Scottish Environment Link carried out a three-year study into the impact of the tracks.
It concluded planning legislation was still not strong enough to protect the landscape.
In many cases, hill tracks can be bulldozed through land without seeking permission from planning authorities.
Despite some tightening of the procedures in 2014, the "Changing Tracks" report said the numbers were "out of control."
Hill tracks for agricultural land is classed as "permitted development" which exempts it from requiring planning permission.
Campaigners argue that some sporting estates use the exemption as a loophole to avoid scrutiny. Land managers insist the current process is working well.
Helen Todd, from Ramblers Scotland, said: "This major new report makes a compelling case for removing permitted development rights for agricultural tracks - to improve local democracy and help safeguard our most precious landscapes for future generations.
"For too long, landowners have been able to expand tracks further and further into wild landscapes with limited oversight from the public or authorities."
In 2014, the Scottish government made it a requirement for estates to give prior notice before constructing new tracks but stopped short of requiring permission.
The report suggested that hill tracks have continued to appear on wild landscapes since the change, often badly-sited or poorly constructed.
With a new Planning Bill going through parliament, the group said the loophole should be tightened.
An amendment to the bill - tabled by Green MSP Andy Wightman - would remove the exemption for land where field sports take place.
Mr Wightman said: "We're talking about tracks in very, very visible locations, at high altitude often, in areas that are quite special.
"The Cairngorms National Park in particular has long had concerns about the proliferation of these tracks and they want to regulate and control them. In other parts of the country too I think it will stop some of the worst, most damaging, tracks.
"We will still get one or two maybe, built by farmers or by foresters now and again, but they are not the main source of the problem.
"It should, I think, substantially reduce the impact we've seen."
The report concluded that the "prior notification" system did not contain sufficient scope to allow authorities to decide whether or not a track qualified for an agricultural exemption.
It also suggested some land owners did not take the system seriously, submitting "poor quality applications with minimal detail".
A spokesman for Scottish Land and Estates, which represents landowners, said: "Hill tracks are a vital component to many rural businesses across Scotland without which many jobs and therefore communities could not be sustained.
"We agree that tracks should be constructed in a manner that befits their surroundings, in line with the Scottish Natural Heritage guidance on constructed tracks in the Scottish uplands.
"Land managers work hard to ensure that high standards of hill track construction are being met through the prior notification and approval process which was implemented in 2014."
He added: "Requiring full planning permission would add considerable cost to an already expensive undertaking affecting businesses of every shape and size in rural Scotland.
"The nature of the work, and the weather, means that flexibility is essential. We believe the current process is generally working well but if issues have been identified then a consultative and pragmatic approach is preferable when the livelihoods of people in rural communities could be impacted."