US opposition to the proposed pact sparked "heated debate" at a UN Environment Programme (UNEP) meeting here that ended instead with calls for voluntary public-private partnerships to reduce mercury levels, they said.

"The United States vigorously opposed a legally binding treaty and managed to defer it to the next session of the UNEP governing council," said one diplomat who closely followed the proceedings.

"The US does not like binding treaties," said another diplomat, who, like the first, spoke on condition of anonymity. "It generally hates bureaucracy (and) it fears that such a move would weaken its industries."

A 2003 UNEP study found that coal-fired power plants and artisanal mining of silver and gold were a major source of mercury found in the earth's air, soil and waterways and recommended action to reduce its presence.

In response, several governments, including members of the European Union, called for a legally-binding to ban mercury, which can cause brain damage in unborn children and infants and possibly impair their nervous systems.

"We all realise that this is a problem and we really need to take action as soon as possible," said Swedish Environment Minister Viveca Bon.

But the United States, which relies heavily on coal-generated electricity, objected, arguing that more study was needed before moving ahead with discussions on a treaty and proposing the partnerhip schemes as an alternative.

"We came here with a position that we wanted to take immediate action through these partnerships and that we wanted to defer a decision on a legally binding instrument until we have results on this partnerships," said Claudia McMurray, the senior diplomat who led the US delegation to the UNEP meeting.

"The (United States) came forward with this (partnership) idea and we are very pleased that we were able convince other countries that this is the credible way to move foward," she told AFP.

McMurray also rejected charges that the United States was not doing enough to stem the presence of mercury, noting that emissions had been reduced by 45 percent since 1990 and that new rules requiring a 70-percent cut in emissions by coal-fired power plants would soon take effect.

Instead of endorsing the opening of talks on a treaty, the conference urged nations to launch partnerships with industry to develop ways to reduce mercury, raise awareness of its risks to vulnerable groups and called on UNEP to carry out a comprehensive study its presence around the world.