A customs official, Arshad Moghul, claimed in Lahore that the 399 ancient tiles were found hidden beneath new tiles in a box being sent by Mrs Khan, daughter of the late Sir James Goldsmith, to her mother in London.
He said the artefacts were more than 300 years old and had been removed from buildings from the Moghul period. "We are seeking experts' opinion. If the tiles prove to be as old as we think they are, we will register a case against Jemima under the Antiques Act."
After winning the cricket World Cup for Pakistan in 1993, Mr Khan entered politics. In 1995 he contested elections against Nawaz Sharif, the Prime Minister, in Lahore. Although he lost, his unsuccessful attempt to enter parliament caused bitter rivalry between him and Mr Sharif's Muslim League party.
Mr Khan described the claim as "baseless" and said the government was running a campaign to defame him. He said the tiles were only 50 years old and that his wife had bought them in a shop in Islamabad.