This is based on speculation that some of the countries that abstained from last month's vote in the legal committee have now been persuaded to take a stand in favour of a total ban. As a result, a group of leading embryo researchers is seeking support to head off any such move next week, which one critic describes as "legislation by stealth".

Countries that supported Costa Rica's original proposal include the United States and several Muslim and predominantly Catholic countries. Although it remains uncertain whether the treaty would now be supported by a majority of countries, the Costa Rican delegation is reported to be keen to revisit the issue.

Bruno Stagno, Costa Rica's ambassador to the United Nations, told the news service Wired News that "We (have) decided (that) we should seek to reopen the issue."

But Alan Trounson, director of stem cell research at Monash University in Australia says that

A total ban on all forms of human cloning "would cast a pall on critical research that will provide our best chance of discovering alternative methods of generating stem cells suitable for [organ] grafting".

Trounson is a member of the Science Advisory Board of the Genetic Policy Institute (GPI), an organisation based in Florida that has organised a campaign to oppose any efforts in the United Nations to institute a ban on therapeutic cloning.

Bernard Siegel, executive director of the GPI, describes the legal committee's decision to delay making a recommendation as "unfortunate" for those seeking a ban on reproductive cloning. "But it at least preserved the hopes of millions of disease victims by not stopping therapeutic cloning research," he says.

In a statement issue by the GPI, Ian Wilmut, the leader of the team who produced the first cloned mammal, Dolly the sheep, said that any failure to proceed with what is technically referred to as stem cell nuclear transfer (SCNT) "is the equivalent to turning our backs on one of the great medical advances of our time".

Wilmut, who is also a member of the GPI science advisory board, has written to the United Nations asking for approval "of UN initiatives outlawing human reproductive cloning, but which allow for the promise of therapeutic cloning (SCNT)".

Siegel says that there is "major concern" among United Nations officials and diplomats that the proponents of a ban on therapeutic cloning, principally the US government, will attempt to "strong-arm" the General Assembly to reject the Legal Committee's recommendation of delay and instead force a vote on the total ban.

"This effort represents a secretive ploy to avoid public scrutiny and debate, and further, would defy United Nations standard protocols," says Siegel. What is happening in the UN is the antithesis of democratic discussion. It is more like secret diplomacy, with the lives of millions of disease victims at stake."