The Elephant Rocks, in the Waitaki Geopark near Duntroon, have had an increase in visitors chipping off pieces of the rocks, carving their names into them and spray-painting graffiti.
The land is privately owned by the Fenwick family.
The family were frustrated with the vandalism over the last 18 months, Maylene Fenwick said.
"I just can’t see their logic — it doesn’t regrow.
"If people keep damaging it, we’ll have to close it."
They had also encountered "entitled" freedom campers who were also causing issues.
Mrs Fenwick was worried about the future of the geopark if they had to close the rocks.
Waitaki Whitestone Geopark Trust chairwoman Rachel Plieger said potentially losing the Elephant Rocks was a big concern.
"This is somebody else’s property.
"These rocks are very generously opened to the public by the landowners, but I could understand they may not want to do that if the public don’t respect it.
"The actions of a few could, frankly, ruin it for the many."
"People fail to recognise that if everyone wants to take a little piece of history home with them, what they’re doing is taking it away from future generations."
The geopark trust board actively discussed how to remedy the situation, but unfortunately did not have a lot of options, Ms Plieger
said.
"We would like to support our landowners more than we have capability or finances to do currently.
"This is something we see ourselves striving to do but it’s not something we’re currently able to do."
The Elephant Rocks are one of the best known geosites in the Waitaki Whitestone Geopark and with their easy access from the road, they are a popular stop for visitors.
— additional reporting Brendon McMahon
