Proposals to overhaul organ donations and boost the number of transplants in the UK by 1,200 a year have been backed by the government.
Thousands of people are waiting for organ transplants
Health Secretary Alan Johnson supported 14 proposals to improve the system such as a UK-wide donation organisation.
A system of "presumed consent", where everyone is considered a donor unless they opt out, was not among proposals.
Mr Johnson said he was attracted to the idea. The Tories have accused Gordon Brown of a "U-turn" on the issue.
There are more than 8,000 people waiting for organ transplants in the UK - a figure which rises by about 8% a year.
Among proposals outlined by the Organ Donation Taskforce were 24-hour organ retrieval teams, a doubling of the number of transplant co-ordinators and a UK-wide minimum period in which donor co-ordinators must be notified of patients whose death is expected.
Other suggestions included reporting rates of referral, identification and approaches to families by individual NHS trusts, and reimbursing trusts which aid the process of organ donations.
The aim is to boost the number of organs being donated by 50% within five years. The Department of Health said work would begin immediately to implement the plans.
Professor Peter Weissberg, of the British Heart Foundation, said the recommendations had to be adopted "in full" if the 50% goal was to be achieved.
The issue of presumed consent will be examined separately and a report is expected in the summer.
The prime minister said on Sunday it had the potential to close "the aching gap" between the benefits of transplant surgery and the limitations of the existing consent system - in the UK 40% of relatives refused to give consent for donation.
In theory the system - used in Spain - allows hospitals to take organs unless people specifically opt out of the scheme, but in practice families are also consulted.
The taskforce's chairwoman, Elisabeth Buggins, told BBC Radio 4's Today programme that she expected those recommendations to be adopted, which she said could "dramatically improve" the donor situation - before they consider whether a system of presumed consent is necessary.
She added: "Whatever the system, whether it's presumed consent or our current system, families are always involved and nobody would retrieve organs against a family's wishes."
Mr Johnson said the prime minister had not said presumed consent should definitely be introduced, but had been "kicking off a national debate".
But he added: "He's attracted by what happens in Spain, as am I."
But shadow health secretary Andrew Lansley has written to Mr Brown asking why he voted against it in 2004, and how it would differ in practice from current rules.
In a letter to the prime minister, shadow health secretary Mr Lansley urges him to "clarify what his policy on organ donation now is, including whether he intends to bring forward new legislation".
He added: "According to press reports, you continue to believe that organs should not be taken against the wishes of a deceased's family.
"So, in what practical way is this different from the current situation? Why should we seek to breach the principle of consent in law while maintaining it in practice?"
Several patient groups are against a system of presumed consent, arguing that it is not up to the state to decide what becomes of people's bodies when they die.