The supermodel, who split from Leonardo DiCaprio last year, claimed that she felt violated after a screening by a female airport security worker in the English capital city.
She told Twitter followers that the incident "left no doubt about [the woman's] sexual preferences".
Refaeli - who didn't specify which airport she was at - took to the micro-blogging site after completing the check-in process before catching a flight.
She said: "I got a security 'patdown' by a woman at the airport that made me feel very uncomfortable and left no doubt about her sexual preferences."
Last year, Dancing with the Stars professional Cheryl Burke claimed a TSA agent got extremely hands-on around her crotch.
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