Bereaved families have vetoed the donation of organs from hundreds of registered donors in the last five years, new figures show.
NHS Blood and Transplant (NHSBT) data suggests relatives blocked transplants in 547 - or one in seven - cases since 2010.
The body said it would no longer seek a family's formal consent in order to reduce the number of "overrides", according to the BBC.
The bereaved will be given a leaflet which explains consent remains with the deceased, although they can still block donation by providing reasons in writing.
NHSBT estimated the blocked donors would have provided organs for 1,200 of the 6,578 patients on the waiting list for a transplant, while not asking relatives could result in the number donors rising by 9%.
Sally Johnson, director of organ donation and transplantation at NHSBT, told the broadcaster: "We are taking a tougher approach - but also a more honest approach.
"My nurses are speaking for the person who has died. People who join the register want and expect to become organ donors. We do not want to let them down.
"We have every sympathy for families - and of course we do not want to make their grief worse. We think this will make what is a hugely distressing day easier for them, by reducing the burden on them.
"The principle that the individual affected is the one who consents applies throughout medicine, and it is not different because someone has died."