Nearly two thirds of French people say they don't trust the government to defend the country's interests in negotiations on a vast new EU-US trade deal, a poll published Friday showed.

Even more -- 69 percent -- lack confidence in the European Commission in the thorny talks with Washington aime at sealing a pact that would create a free-trade zone covering 850 million people, according to the survey by the Ifop institute.

But over half of those questioned said they believed that unions, non-governmental organisations and associations were credible in fighting for their interests, the poll for Atlantico news website showed.

Carried out between April 28 and May 2 among 1,003 people, the polling wrapped up the day before President Francois Hollande warned that Paris would reject the trade deal "at this stage" because the country opposes "unregulated free trade."

Washington and Brussels want the Transatlantic Trade and Investment Partnership (TTIP) completed this year before US President Barack Obama leaves office, but it has faced mounting opposition on both sides of the Atlantic.

Environmental pressure group Greenpeace on Monday released a trove of leaked documents about the closed-door negotiations, claiming that a deal would inflict a dangerous lack of standards on US and European consumers.

The French survey indicated that 68 percent of those questioned believed that US companies would be the big winners of the mega-deal, while only 32 percent judge it will be an asset for French firms.

Some 48 percent said a TTIP deal constitutes a threat for French workers.

A poll in neighbouring Germany earlier this week also showed that people in the eurozone's biggest economy were increasingly wary of the trade pact, with some 70 percent saying it would bring "mostly disadvantages".

Chancellor Angela Merkel has voiced hopes for a deal by year-end.