Participants at a Vatican conference on organ trafficking challenged China on Tuesday to allow independent scrutiny to ensure it is no longer using organs from executed prisoners, saying Chinese assurances aren't enough to prove the transplant programme has been reformed.

Sparks flew in the afternoon session of the meeting as China's former vice health minister, Dr Huang Jiefu, sought to assure the international medical community that China was "mending its ways" after declaring an end to the prisoner harvesting programme in 2015.