Following the recent bad weather, members of the public are being urged to take extra care when they visit the County's local beaches.
In particular people are being warned to avoid climbing sand dunes or digging into them as they could be unstable.
Pembrokeshire County Council, the Pembrokeshire Coast National Park Authority and the National Trust issued the beach warning ahead of the upcoming half term holidays.
The organisations also advise people to avoid climbing or sitting at the base of cliffs as they could also be prone to landslides following heavy rainfall.
In their joint warning the County Council, National Park Authority and National Trust say that the severe tidal surges and storms experienced both this month and last have resulted in a great deal of coastal erosion along the Pembrokeshire coast - with sand dunes in particular being badly eroded.
Sand dunes normally have a sloping profile to the beach but many dune systems have been left with near vertical or even overhanging edges facing seaward.
"The dunes will in time settle through a natural process and slump to form gentler slopes to the beach, however, at present their sheer edges are very unstable and may risk sudden collapse," they said.
"Our beaches are still there to be enjoyed in the half term holidays but please supervise children carefully and avoid sand dunes on beach heads for the time being until the dunes have become more stable."
Dune systems are found at Tenby South Beach, Freshwater East, Manorbier, Broad Haven South, Barafundle, Freshwater West and Newport.