A series of plots in the village of Balquhidder, Perthshire, are up for auction at between £8,000 and £15,000 with fishing rights.
They are described as "the perfect retreat from the stresses and strains of a busy modern life" and a "perfect location for those who love the outdoors" by Future Property Auctions which is marketing them.
But Loch Lomond & The Trossachs National Park Authority officials say they are are in an area at risk of flooding, so any development would be unlikely to receive planning permission.
Outlaw Rob Roy was buried in Balquhidder Parish Church in 1734, has since been immortalised in song and prose, and is an attraction for many visitors throughout the year.
Concerns were raised about certain marketing material for the plots which did not directly warn about the status of the land, amid fears buyers would be "disappointed" if they splashed out and then found they were unable to erect a shed or holiday home.
But Future Property Auctions, based in Glasgow, which is selling the land, dismissed the concerns as "scaremongering".
It comes as Loch Lomond & The Trossachs National Park Authority officials have begun investigating unauthorised development in the scenic national park carried out on land between Stroneslaney Road and the River Balvag near Balquhidder.
Planning contravention notices have already been issued, requiring detailed information on what officials described as "significant" changes to create a vehicle access and track, with no planning permission sought or granted for the work.
But officials have also raised concerns over six plots of up to 1.66 acres at the same site being marketed for sale at auction.
A plot of 1.66 acres, the biggest of the bunch, had an initial asking price of £15,000 while others were marked as "price on application".
Officials said the six plots for sale are the latest in a series of cases where land is advertised for sale at an attractive price.
The promotional material stated: "The village attracts many visitors from around the world who come to see the final resting place of Rob Roy."
In 2020, planning enforcement action was taken to stop development of a site dubbed Little America near Gartocharn, where small plots had been sold without highlighting the constraints on the land and where unauthorised work was carried out.
Stuart Mearns, director of place at the national park authority said: "Unfortunately, what we are seeing is plots of land being sold to people who are not fully aware of these constraints and are left deeply disappointed when they cannot, for example, use the plot to build a new home, a holiday home, park motorhomes or put up a small storage shed.
"Anyone interested in purchasing these plots should seek advice from suitably qualified persons or seek the National Park Authority's planning advice."
John Morris, general manager of the auction firm said: "We have not stated anywhere in any description that they would be suitable for development.
"They are just bits of land if someone wants to own a bit of Scotland.
"The sellers are perfectly within their right to sell this land in chunks with fishing rights."