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.
A new advert highlighting the issue shows a man's choice to donate his organs being overridden by family members because he did not talk to them about his decision to join the donor register.
Health Secretary Vaughan Gething said awareness and understanding of presumed consent donation was increasing but more work could be done.
He said: "We have seen huge improvements in our consent rates, in March 2013 they were just 50% but in March 2017 they increased to 64%.
"However while there are people dying waiting for their transplant we must work harder to further increase the consent rate to have a significant impact on reducing transplant waiting lists.
"Your family will be involved in any discussions about organ donation if, when you die, you are in a position to donate your organs."
In December 2015, Wales became the first country in the UK to move to a presumed consent organ donation system.
It means unless somebody registers to opt out, their organs will be donated after they die. But family members can still go against that decision.