Police have open an inquest docket after a woman died on board a British Airways flight to Johannesburg from Cape Town on Wednesday.

Police spokesperson Lt-Col Katlego Mogale said the woman was certified dead on arrival at the OR Tambo International Airport in the afternoon.

"According to medics, she died on the flight. However, an inquest will determine when she died," said Mogale.

British Airways and Comair were not immediately available for comment.