Organ donors in Wales are being urged to speak to their families about their choice to donate to prevent relatives overriding their decision.
Figures show 21 families denied consent for organs to be given or did not support deemed consent in 2016/17.
The Welsh Government said this could have resulted in 65 extra transplants, with three organs retrieved per donor on average last year.
Adults in Wales are regarded as agreeing to donate unless they opt out.
Michelle Powell, a specialist nurse for organ donation, said medical staff had to be understanding of families’ concerns about organ donation.