Presumed consent for organ donation has been rejected by an expert government advisory committee.
The UK organ donation task force said the risks of moving to the system outweighed the potential benefits.
Presumed consent could prompt anti-donation feeling and campaigning and damage the relationship between clinicians, very ill patients and their families, the committee's report said.
Some patient groups felt that "assuming consent from silence belongs to a more paternalistic era".
The task force said: "It became increasingly clear that it would be both complex in practical terms and also costly to put in place an opt-out system that could command the trust of professionals and members of the public."
The review, called The Potential Impact of An Opt Out System in the UK, was carried out in response to concerns about the shortage of donor organs. Prime minister Gordon Brown had suggested moving to presumed consent could be a solution.
However, the review said an apparent trend of high donation rates in countries with opt-out systems was not reliable.
Health secretary Alan Johnson today welcomed the report but said that if voluntary organ donations did not increase the government might look at presumed consent again.
"The task force has presented a well-balanced analysis of a substantial body of evidence drawn from a wide range of groups, including healthcare professionals, organ recipients, donor families, representatives of faith groups, and members of the public," he said.
"The task force conclude that donation rates equivalent to those achievable through the best presumed consent systems could still be possible without a change in the legal framework - and I therefore accept their recommendation that we should aim to achieve these rates without the complications associated with a change in the legal position.
"If, however, we do not see the number of organ donations rising and progress is not being made we will revisit the issue of whether a change in the law is needed."