MTV's satellite music channel has applied for permission to stage a one-off "unplugged" concert in the famous Cango Caves - starring Coldplay.
The Oudtshoorn municipality has been approached by a company called Hunta Entertainment.
According to council documents, there is a moratorium on events in the caves after damage caused by a succession of Passion plays and concerts in the past.
Council officials at first recommended that the application be turned down "to keep the conservation integrity of the caves intact and ... focus on long-term conservation for generations to come".
Another council official said: "The opportunity is on a very grand scale and undoubtedly a tempting one. Does one forfeit a conservation integrity that took years to restore for a once-offâ quick marketing fix?"
But Hunta has persuaded the municipality to allow it to appoint a scientist to determine how a concert could be held without doing the caves any harm.
It will hire "cave specialists" and promises to "revere the cave as an exquisite, very special venue".
Several councillors, including the deputy mayor, James Swigelaar, support the proposal because of its marketing value to the caves and the region.
"The exposure from this event is unsurpassed, reaching an audience of 900 million viewers. In conservative monetary terms such a venture is worth $2 million (R14m)," he wrote to the Cape Argus yesterday.
If approved, the concert would take place in the last quarter of the year or the first quarter of next year.
Hunta has proposed building a performance platform inside the Van Zyl Chamber, the main show cave, with seating for an audience of 800.
It would give any profits from ticket sales, other sponsorships and broadcast revenue to a conservation charity after costs were recovered.
The documents presented to council also said Coldplay lead singer Chris Martin "has become the modern mouthpiece for a generation of young people who believe that saving the planet is no longer a job for individuals, but for the masses".