A stone circle in Co Kerry, one of the largest in the south-west, has been turned into "a feature garden", according to an environmental group. It has complained to Bord Fáilte, Kerry County Council and the Garda.
Friends of the Irish Environment has complained that the traditional access to the Kenmare Stone Circle, a large monument with a boulder dolmen and cap stone in the centre, has been blocked.
It says that members of the public who wish to go to visit are charged an entrance fee when the monument is open.
The group also says that "garden-type" conifers have been planted around the monument. These impeded views of the surrounding countryside, and a wooden cabin has been set up to collect the charges from the public.
"Kenmare Stone Circle is one of the most accessible in the country, being directly on the edge of the towns.
"What has been done to it is having a negative impact on its amenity value for visitors," Ms Caroline Murphy, director of Friends of the Irish Environment, has said.
However, landowner Mr Joe Arthur said the small charge had been imposed in order to maintain the monument and keep it in order. The other extreme was to neglect it and not supervise it.
He said there have been problems with encampments and such at certain times of the year, which could damage the monument if unsupervised access was allowed.
For the past 14 years, as landowners, they have guarded against such intrusions.
Insurance, he said, was also a major consideration in the decision to charge visitors. The alternative was not to allow access. They had constructed a new access as the older one was slippery and dangerous.
He said the site, on a 40 acre-property, was going on the market shortly.
A spokesperson for Dúchas, the Heritage Service, said it would not be necessary to purchase the site in order to protect it. It was looking at the matter of the conifers.
If these were within the buffer zone, they would have concerns.
There was a minimum 20ft buffer zone around most monuments.
Dúchas usually preferred "a more natural look" around monuments.
The spokesperson said in general the Arthurs had maintained the site "extremely well", and had protected what was a very important monument.
Several monuments were on private land, and the landowners charged for access. Dúchas had no control over that.
The spokesperson added that litigation and high insurance costs had destroyed free access to monuments.