Bulgarian Olympic Committee (BOC) general-secretary Belcho Ivanov has replaced Ivan Slavkov as president.
Bulgarian Ivan Slavkov was secretly filmed by Panorama
The change at the helm comes after Slavkov's suspension from the IOC over corruption allegations, a charge that has angered BOC officials.
"It's terrible just before the Games and the whole delegation will be very disappointed. It's unnecessarily severe and extreme," said a spokeswoman.
"The decision should have been made only after the full inquiry was over."