"This treaty could represent growth and jobs for Europe on condition that it is balanced," Michel said in an interview published in Belgian business daily L'Echo.
"What is on the table doesn't seem to be. So, for the moment, I prefer to say that it's not right and that perhaps we will resume negotiations later. That said, there is an electoral reality in America. They are campaigning."
Washington and Brussels are officially committed to sealing the Transatlantic Trade and Investment Partnership (TTIP) before U.S. President Barack Obama leaves office in January, but serious doubts have surfaced, according to Reuters.
Last week French Trade Minister Matthias Fekl said he would request a halt to the talks at an EU trade ministers' meeting on Sept. 23 after German Economy Minister Sigmar Gabriel had declared that talks were "de facto dead".
Observers have said Fekl and Gabriel are responding to public mistrust of the TTIP proposals which critics say would lower environmental and food standards and allow foreign multinationals to challenge government policies. Both France and Germany are due to hold elections in 2017.
EU trade chief Cecilia Malmstrom, who is in charge of trade negotiations for the European Union, said last week she was surprised to hear the comments before she had been able to brief trade ministers at the meeting in Bratislava.
"They are advancing. They are difficult. We knew that from the beginning, but they have not failed," she told reporters, adding the aim was still to conclude talks before President Barack Obama's term ends in January.
"That is still our aim and if that is not possible it makes sense to make as much as progress as possible," she said. "It's very difficult to say this is a bad deal because there isn't any deal yet. Nothing is concluded until everything is concluded."