After years of battling each other on trade issues, US and European officials are contemplating a dramatic change in direction: joining together in what could be the world's largest free trade pact in an attempt to boost their struggling economies.

Discussions are in the most preliminary of stages and there would be significant obstacles to overcome, including sharp differences on agriculture, food safety and climate change legislation. Still, top European Union and US officials have said they want to see it happen. And America's main labour group, often the biggest opponent of US trade pacts, says it wouldn't stand in the way.

Last month, Secretary of State Hillary Rodham Clinton signalled the Obama administration's interest during a speech on trans-Atlantic relations.

"If we get this right, an agreement that opens markets and liberalizes trade would shore up our global competitiveness for the next century, creating jobs and generating hundreds of billions of dollars for our economies," Ms Clinton said.

European officials, including EU Commissioner for Trade Karel De Gucht, have also expressed enthusiasm. Both sides are awaiting a report within weeks by a working group they appointed to study the issue. A positive recommendation could lead to negotiations early next year.

The interest in Washington to take on a big free trade deal is somewhat surprising. US free trade negotiators have had a tough slog since the politically fraught debate over the NAFTA agreement with Mexico and Canada in 1991. Since then, it has become increasingly difficult to push big deals through Congress amid opposition from labour groups. Smaller deals with individual countries, including Peru and South Korea, have been approved.

Efforts to negotiate further reductions in tariffs between the more than 150 countries in the World Trade Organization also have stalled in recent years, in part over disagreements between the US and the EU.

Negotiators would face a host of tricky issues that have previously led to trans-Atlantic trade spats. The two sides currently are fighting over the EU's carbon trading scheme that could penalize airlines not meeting EU standards.

There are also substantial disagreements over intellectual property enforcement and food safety issues. More broadly, agricultural issues, including EU restrictions on the use of genetically modified foods and pesticides, are likely to challenge negotiators. Mr Tyson Barker, who directs trans-Atlantic relations at the Washington office of Germany's Bertelsmann foundation, said the agricultural issues would be particularly sensitive in France.

"This will not be smooth sailing in Europe, by any stretch of the imagination," he said.

In the US, the negotiations do appear to have the backing of both big business and big labour.

Labour unions have opposed previous US free trade deals with developing countries, arguing that American workers would be at a competitive disadvantage because inferior environmental and labor standards in those countries allow for lower wages. But the giant US labor umbrella organization, the AFL-CIO, said it wouldn't have those concerns in a deal with the EU.

"The AFL-CIO believes that increasing trade ties with the EU could be beneficial for both American and European workers," the union said in a statement about the working group studying a potential deal.

TODAY