Police believe that a small number of people may have left the beach following the landing of two boats containing suspected illegal immigrants at Winchelsea, near Rye, on Thursday morning (August 22).
A group of adults and children were transferred to immigration officials after the boat, believed to have crossed the Channel, landed between Dogs Hill and Rye Harbour.
However, it is thought that some them, possibly a family including children, may have left the beach on their arrival and there is concern for their safety and welfare.
Chief Inspector Anita Turner said: "We want to make sure that these people are safely ashore and that they are okay. If you do come across them, please call us on 999 immediately quoting serial 462 of 22/08.”