A conservative Assembly Member from Wales has opposed the introduction of presumed consent in his region and asserted that such a move does not necessarily lead to greater availability of organs for transplant.
The region's Health Minister Edwina Hart recently announced that Wales would pursue a legislative competence order (LCO) in a bid to move to an opt-out system.
Wales, like the rest of the UK, currently has an opt-in system, which depends on people joining the organ donor register and conveying their wishes to their families.
Presumed consent would assume that everyone wants to be an organ donor after death unless they have opted out during their lifetime.
But relatives' opinions would also be taken into consideration.
But Assembly Member Jonathan Morgan contends the presumed consent doesn't necessarily work. Citing the example of Spain in his blog, Mr.Morgan said, there was to evidence to show that organ donation rates increased in Spain when its soft system of presumed consent was introduced in the 1970s.
Organ donation rates only began to improve when the Spanish government invested in clinical training giving medical staff the confidence to approach grieving relatives about organ donation, he argued.
"They also invested in the transplantation units and the coordination of the organs that were available," he said.
"There is no evidence to suggest that the change in the law did anything. The investment though was absolutely key."
The Assembly Member from Cardiff North also lampooned the presumed consent move as one that depended on the laziness of the people, many of whom will never have expressed an opinion about organ donation.
"There is a question as to whether it is better for the UK as a whole to have a common system for regulating the use of organs or whether a nation like ours should have a separate legal system," he said.
Morgan was chairman of the National Assembly's health committee when it carried out an inquiry into organ donation last year, which ultimately rejected presumed consent.
At the time he favoured a review of capacity at transplant units, investment in staff training and better promotion for organ donation.
The Welsh Assembly Government has since invested in the Donate Wales campaign to persuade more people to join the organ donor register.
Health Minister Hart said: "Cabinet colleagues have agreed with my proposal to explore the possibility of introducing a soft opt-out system for organ donation in Wales and that a bid for an LCO be submitted as part of the annual trawl for legislative items.
"This will take time to achieve so we must continue to do all we can to raise awareness of this issue and encourage people to sign up to the organ donation register."