Beach Break Live, a festival aimed at students, is due to happen from 14-18 June, and has applied for a licence for live music until 4am.
A Western Mail article reports that the festival will feature performances from the likes of Ellie Goulding, Calvin Harris and The Futureheads, and that concerns have been raised that tickets have gone on sale "weeks before an enquiry into concerns about the suitability of the site to hold the event".
Pembrey Country Park is a Site of Special Scientific Interest due to its ancient sand dunes and its unique flora in habitat. Dr John Etherington told the Western Mail, "Sand dunes are crucially important parts of our natural solar-powered coastal defences and can be trashed by human feet.
"If the gig gets permission it will take place in the fledging season when bright lights and decibels will disturb not only birds and bats but other residents and visitors."
The organisers of Beach Break Live were unavailable for comment.
